Skkn hóa học thpt (1)

Vì vậy, vai trò của nhà trường phổ thông là trang bị cho học sinh kiến thức và kĩ năng để các em có thể tự tin sử dung tiếng Anh trong giao tiếp và tra cứu thông tin, kiến thức trên inte

Giáo viên, TTCM: Phạm Thị Dung

Tổ Hóa Học, trường THPT Nguyễn Khuyến

I Điều kiện, hoàn cảnh tạo ra sáng kiến

- Trong xu thế hội nhập quốc tế ngày càng sâu rộng, việc học và sử dụng tiếng Anh trong giao tiếp và trong việc tra cứu tài liệu nước ngoài là một yêu cầu vô cùng quan trọng của lực lượng lao động trẻ Vì vậy, vai trò của nhà trường phổ thông là trang bị cho học sinh kiến thức và kĩ năng để các em có thể tự tin sử dung tiếng Anh trong giao tiếp và tra cứu thông tin, kiến thức trên internet và các tài liệu nước ngoài, để các em có thể thích ứng với các môi trường và hoàn cảnh khác nhau

- Tỉnh Nam Định là một trong những tỉnh đầu tiên trong cả nước tổ chức hội thi

―Giải toán và các môn khoa học bằng tiếng Anh‖ Mục đích của hội thi là thúc đẩy phong trào học tiếng Anh trong nhà trường cũng như kích thích khả năng sử dụng công cụ tiếng Anh để tìm hiểu môn học khác, giúp giáo viên và học sinh tiếp cận những kiến thức khoa học lý thú từ đó so sánh được những nội dung được đề cập trong sách tiếng Việt với những kiến thức cập nhật trong các tài liệu nước ngoài, kích thích khả năng tự học, tự khám phá và tình yêu khoa học của các em học sinh

- Từ năm học 2015-2016, Sở GD-ĐT Nam Định đã bắt đầu tổ chức hội thi ―Giải toán và các môn khoa học bằng tiếng Anh‖ Cho đến nay, hội thi vẫn diễn ra đều đặn ( trừ năm học 2019-2020 và 2021-2022: không tổ chức do diễn biến phức tạp của dịch bệnh), tạo nên phong trào dạy học và sử dụng tiếng Anh trong các môn khoa học trong các trường phổ thông trong Tỉnh ( đặc biệt là những trường chất lượng cao)

II Mô tả giải pháp

1 Mô tả giải pháp trước khi tạo ra sáng kiến

- Một thực tế dễ nhận thấy việc học sinh chủ động sử dụng tiếng Anh để tìm kiếm thông tin phục vụ cho mục đích học tập các môn khoa học là rất hạn chế Nguyên nhân của việc này có thể là:

+) Trước hết, mục tiêu học tập của đại đa số học sinh hiện nay là để phục vụ các

kì kiểm tra, kì thi Các đề kiểm tra hay đề thi hiện nay đều theo mô tuyp là các câu hỏi đóng, nặng về tính toán, các câu hỏi mở rất hiếm thấy Vì vậy để được điểm cao các em thường chọn giải pháp luyện giải những bài toán khó cùng các thầy cô giáo hay trong các

+) Rất nhiều em học sinh năng lực tiếng Anh hạn chế Các em rất ngại sử dụng tiếng Anh trong giao tiếp và kể cả trong việc tra cứu thông tin

- Từ thực tế trên, chúng ta thấy rõ vai trò vô cùng quan trọng của nhà trường và đặc biệt là đội ngũ các thầy cô giáo trực tiếp giảng dạy trong việc kích thích khả năng tư duy và nhu cầu tìm hiểu kiến thức mới liên quan đến bài học của các em học sinh

- Tại trường THPT Nguyễn Khuyến, trong những năm gần đây, trong các bài kiểm tra định kì, nhà trường yêu cầu các môn khoa học có tối thiểu hai câu hỏi trắc

nghiệm bằng tiếng Anh ở mức độ nhận biết và thông hiểu Vì vậy, trong quá trình giảng dạy, các thầy cô đã cung cấp được cho các em học sinh những từ vựng chuyên môn liên quan đến chương, bài; giới thiệu cho các em các trang wed phù hợp để các em tra cứu thông tin, đồng thời cũng hướng dẫn các em cách đọc tài liệu bằng tiếng Anh ( đặc biệt với đối tượng học sinh khá, giỏi)

- Với bản thân tôi, qua kinh nghiệm bồi dưỡng học sinh tham gia hội thi‖ Giải toán

và các môn khoa học bằng tiếng Anh trong bộ môn Hóa học‖ một số năm tôi thấy việc lồng ghép tiếng Anh vào các môn khoa học trong nhà trường muốn đạt được hiệu quả cần phải thực hiện từng bước, không nóng vội

Giai đoạn một: Làm quen với tiếng Anh trong Hóa học: Cung cấp cho học sinh

ngôn ngữ hóa học cơ bản: Tên các nguyên tố trong tiếng Anh, cách đọc tên các hợp chất (axit, bazo, muối, oxit) trong tiếng Anh, các thuật ngữ trong phòng thí nghiệm hóa học, các cách thu khí, tách chất, các loại phản ứng hay gặp

Giai đoạn hai: Hướng dẫn học sinh cách trình bày một bài toán hóa học trong tiếng Anh: Lựa chọn những bài tập điển hình, đơn giản , cung cấp các câu dẫn hay gặp trong lý luận

để học sinh hình dung được cách trình bày một bài hoàn chỉnh theo đúng mạch tư duy logic của các em Từ đó các em sẽ không thấy khó khăn hay ngại đưa tiếng Anh vào việc học Hóa học Trong những năm gần đây, một số trường đại học ( kể cả các trường đại học tốp đầu) đã mở rộng các hình thức xét tuyển đại học, trong đó có hình thức xét tuyển thông qua kết quả học bạ và các giải học sinh giỏi cấp Tỉnh Ví dụ năm học 2019-2020, em Trần Thị Ngọc Anh – 12A3 đã đỗ đại học Kinh Tế Quốc Dân nhờ giải nhất hội thi Giải toán và các môn khoa học bằng tiếng Anh trong môn Hóa học mà em đã tham gia năm lớp 11

nhận SKKN cấp nhành và được Sở KH-CN đánh giá công nhận là sáng kiến có tính ứng dụng cao, được phổ biến rộng rãi, được các đồng nghiệp trong Tỉnh sử dụng và đánh giá

thuyết và bài tập trong sáng kiến ở trên Trong tài liệu này, tôi đã biên soạn 20 đề theo

cấu trúc đề thi học sinh giỏi Hóa học bằng tiếng Anh của tỉnh Nam Định và đã dùng làm tài liệu tự học cho học sinh tôi bồi dưỡng tại trường THPT Nguyễn Khuyến trong hai năm học 2020-2021 và 2021-2022

2 Mô tả giải pháp sau khi tạo ra sáng kiến

Trước hết, chúng ta đều biết dạy và học các môn khoa học bằng tiếng Anh, trong đó

có môn hóa là vấn đề không hề đơn giản đối với cả giáo viên và học sinh Hiệu quả của việc này phụ thuộc vào trình độ chuyên môn, năng lực tiếng Anh, sự nhiệt tình của thầy

cô cũng như tính tự giác, tình yêu với môn học và năng lực nhận thức của học sinh Do

đó, đối tượng tiếp cận của sáng kiến chủ yếu là học sinh và thầy cô dạy môn Hóa học ở các trường THPT chất lượng cao và những thầy cô và các em học sinh tham gia vào kì thi giải toán và các môn khoa học bằng tiếng Anh cuả các nhà trường khác

Đây là hệ thống đề ôn tập, vì vậy để làm tốt các nội dung này, các em đã phải nghiên cứu xong nội dung bằng tiếng Anh môn Hóa học của chương trình lớp 10 và học kì I của chương trình lớp 11 Tất cả những nội dung này đã được tôi trình bày rất chi tiết trong sáng kiến ―Xây dựng hệ thống bài tập hướng dẫn học sinh học các môn khoa học tự nhiên bằng tiếng Anh trong môn Hóa học‖

Mỗi đề sẽ có phần đề bài ( 35 câu trắc nghiệm – 7 điểm và 3 bài tập tự luận – 3 điểm)

và phần đáp án ( bảng đáp án phần trắc nghiệm và lời giải chi tiết phần tự luận) Nội dung các câu hỏi trắc nghiệm liên quan đến những nội dung cơ sở của Hóa học, kiến thức cơ bản về tính chất vật lý, tính chất hóa học, ứng dụng, điều chế của các chất Đặc biệt trong

các bài tập nặng về tính toán Cấu trúc đề ôn tập cũng bám sát theo cấu trúc đề thi của tỉnh, giúp các em ôn tập hiệu quả và tự tin khi tiếp xúc với đề thi thật và làm bài thật tốt

để đạt kết quả cao

I PART I (7.0 points)

Question 1.Felipe is observing how acetic acid (vinegar) and sodium bicarbonate (baking

soda) react with one another in a volcano model What evidence can Felipe look for to indicate a chemical reaction has taken place?

A The volume of the acetic acid increases

B The density of the baking soda decreases

C Gas bubbles are produced

D The baking soda is dissolved

Question 2 During a science lab, Jessica records the following data when Liquid A

(clear) and Liquid B (clear) are combined in a beaker Did a chemical change occur? Why?

A Yes, a new yellow liquid is formed

B Yes, mixing any two unknown liquids will cause a chemical change

C No, there was no change in temperature

D No, there was no change in the state of matter

Question 3 Which of the following description is an example of a chemical change? A.Wood burning in a fireplace B ice melting in water in a beaker

C a cracked rock D boiling water on a hotplate

Question 4 Marlene‘s family goes on an autumn campout to a local state park During

her campout she notices several things that could be chemical changes Which of the following is not considered a chemical change?

A leaves on the trees turning from green to red

B the campfire turning wood into ashes

C.the clouds forming rain from water vapor

D a marshmallow turning black on the outside when cooked over the campfire

Question 5.Compound Z is made from element X and element Y Compound Z is a good

conductor of electricity when molten but not when solid Which statement is correct?

A Compound Z has strong forces of attraction between electrons and positive ions

B Compound Z has strong forces of attraction between negative ions and positive ions

C Elements X and Y are both metals

D Elements X and Y are both non-metals

Question 6 Which diagram shows the outer electron arrangement in calcium fluoride?

A B

C D

Question 8 Which statement about solid calcium chloride is correct?

A It conducts electricity B It has a low melting point

C It has an ionic lattice structure D it has a molecular lattice structure

Question 9 Which statement is correct for all ionic compounds?

A They dissolve in water

B They are formed when metals share electrons with non-metals

C They conduct electricity in the molten state

D They conduct electricity in the solid state

Question 10 The table shows some properties of four substances Which substance is an

ionic compound?

Melting

point/0C

Conducts electricity when solid

Dissolves

in water

Conducts electricity in aqueous solution

Question 12.The graph gives the melting points (m.p.) of mixtures of lead and tin

The graph shows that any mixture of lead and tin must have a melting point that is

A above that of tin B below that of lead

C below that of both tin and lead D between that of tin and lead

A Br2(aq) + 2NaCl (aq) → 2NaBr(aq) + Cl2(aq)

B Br2(aq) + 2NaI(aq) → 2NaBr(aq) + I2(aq)

C I2(aq) + 2NaCl (aq) → 2NaI(aq) + Cl2(aq)

D I2(aq) + 2NaBr(aq) → 2NaI(aq) + Br2(aq)

Question 14 Aqueous copper(II) sulfate solution is placed in an iron container and left to

stand for several days Which statement describes what happens?

A Atmospheric oxygen reacts with the copper(II) sulfate to give black copper(II) oxide

B Some fine iron particles are formed in the solution

C The part of the container in contact with the solution is coated with copper

D The solution turns from green to blue

Question 15 Which reaction is not a redox reaction?

A CaCO3 → CaO + CO2 B 2C + O2 → 2CO

C C + CO2 → 2CO D Fe2O3 + 3CO → 2Fe + 3CO2

Question 16 A student has five reagents

• dilute hydrochloric acid

• dilute sulfuric acid

• dilute nitric acid

• solid calcium carbonate

• solid copper(II) carbonate

How many soluble salts can be prepared?

2FeTiO3 + 7Cl2 + 6C → 2TiCl4 + 2FeCl3 + 6CO

When 500 kg of FeTiO3, 850 kg of Cl2 and 125 kg of C are mixed, which of these

reactants is present in excess? Select all that apply

A FeTiO3 B Cl2 C C D CO

Using the graph, what mass of precipitate will be produced when 50 mL of a saturated solution at 40 °C is cooled to 10 °C?

A 15 B 20 C 25 D 30

Question 21 What volume ( in L) of 2.05 mol L-1 sodium chloride solution should be added to 1.06 L of 1.04 mol L-1 sodium chloride solution to make 2.22 L of 1.26 mol L-1sodium chloride solution upon dilution to volume with water?

Question 24.Jarosite is a white mineral of formula KAl3X2(OH)6, where X is an

unspecified species Which of the following could X be?

A 0.005 mol B 0.01 mol C 0.02 mol D 0.04 mol Question 27 Iron can be produced by reducing iron(III) oxide with carbon monoxide, as

described by the following balanced chemical equation:

Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g)

What mass of carbon dioxide is produced by the complete reduction of 16.0 g of iron(III) oxide?

A 1.5 g B 4.4 g C 6.6 g D 13.2 g

Question 28 A mixture of calcium carbonate and sodium chloride contains 10% carbon

by mass What is the percentage by mass of sodium chloride in the sample?

A 10% B 17% C 50% D 83%

C3H7OH(l) + O2(g) → CO2(g) + H2O(l)

A 0.67 B 0.75 C 1.00 D 1.33 Question 30 When aluminium reacts with hydrochloric acid, aluminium chloride and

hydrogen gas are produced The volume of one mole of hydrogen gas at 25 °C and 100 kPa is 24.79 L When 2.70 g of aluminium reacts with 50.0 mL of 5.00 mol L-1

hydrochloric acid, what volume of hydrogen gas is produced, when measured at 25 °C and 100 kPa?

A 2.48 L B 3.10 L C 3.72 L D 4.96 L

Question 31 Tetraethyl lead, Pb(C2H5)4, has been used as a petrol additive What is the percentage by mass of carbon in tetraethyl lead?

A 10.2 B 14.9 C 29.7 D 32.0

Question 32 A white powder is known to be a mixture of magnesium oxide and

aluminium oxide 100cm3 of 2 mol.dm–3 NaOH(aq) is just sufficient to cause the

aluminium oxide in x grams of the mixture to dissolve

The reaction occurring is Al2O3 + 2OH– + 3H2O → 2Al(OH)4

– 800cm3 of 2 moldm–3 HCl (aq) is just sufficient to cause all of the oxide in x grams of the mixture to dissolve

The reactions occurring are Al2O3 + 6H+ → 2Al 3+ + 3H2O

and MgO + 2H+ → Mg2+ + H2O

How many moles of each oxide are present in x grams of the mixture?

Aluminium oxide Magnesium

Question 33 X and Y are both Group 2 metals

X and Y both form hydroxide compounds, but X(OH)2 is more soluble in water than Y(OH)2 If a piece of metal Y is put into cold water a very slow reaction occurs, and only

a very few, small hydrogen bubbles can be seen What could be the identities of X and Y?

With NaCl , the products are NaHSO4 and HCl

With NaI, the products are NaHSO4, HI, I2, SO2, H2O, S and H2S

What is the best explanation for this difference in products?

A Chloride ions will displace iodine from solution

B Hydrogen chloride is more volatile than hydrogen iodide

C Iodide ions are better reducing agents than chloride ions

D Sulfuric acid is able to act as a dehydrating agent with NaI

Question 35 In some areas, lime - Ca(OH)2, is added to soil to improve crop growth Which statement correctly describes a reason why lime improves crop growth?

A Lime acts as a catalyst which speeds up the release of nitrates into the soil

B Lime is an effective pesticide and protects the plants from damage

C Lime is used to reduce the acidity of the soil

D Lime lowers the pH of the soil

II PART II (3.0 points)

Write the solutions to the following questions in the provided space on your anwer sheet

Question 1 A student wants to prepare 1.00 L of a 1.00 M solution of NaOH (molar

mass : 40.00 g/mol)

a) If solid NaOH is available, how would the student prepare this solution?

b) If 2.00 M NaOH is available, how would the student prepare the solution?

Question 2 When 1.0 mol of solid lead nitrate is added to 2.0 mol of aqueous potassium

iodide, a yellow precipitate forms After the precipitate settles to the bottom, does the solution above the precipitate conduct electricity? Explain Write the complete ionic equation to help you answer this question

Question 3 A solution of ethanol (C2H5OH) in water is prepared by dissolving 75.0 mL

of ethanol (density 0.79 g/cm3) in enough water to make 250.0 mL of solution What is the molarity of the ethanol in this solution?

Mole of NaOH ( after): 1.00x1.00 = 1.00 mol

 mass of NaOH in the resulting solution is: 1.00x40.00 = 40.00(g)

a) If solid NaOH is available,

We weigh 40 grams of NaOH, dissolve in a volumetric flask and stir, then add

water to obtain 1 liter of solution

b) If 2.00 M NaOH is available

Voloume of 2.00M NaOH solution is: 1.00/2.00 = 0.50 (L)

We pour 500ml of 2M NaOH solution into the volumetric flask, then add water to get 1 liter of 1M NaOH solution

Question 2

We have reaction Pb(NO3)2(aq) + 2KI(aq)  PbI2 (solid) + 2KNO3(aq) 1mol  2 mol  2 mol

 we have the net ionic equation

Pb2+(aq) + 2I-(aq)  PbI2 (solid) Because Pb2+ acts just enough to I-, the solution after eaction contains K+ and NO3

So the solution after the reaction conducts electricity because there are free ions

-Question 3

Mass of ethanol is: 75.00x0.79 = 59.25 (g) Mole of ethanol is: 59.25/46.00 = 1.288 mol the molarity of the ethanol in 250ml solution: 1.288/0.25 = 5.15mol.L-1

ĐỀ ÔN TẬP SỐ 2

I PART 1 (7.0 points) Question 1 The plot shows the volume of H2 gas produced as a function of time by the

reaction of a given mass of magnesium turnings with excess 1 M HCl

What graph results from the reaction of an equal mass of magnesium turnings with excess 2 M HCl?

A B C D

Question 2 An ionic compound has the formula XY, know that Y is a non-metal

Which statement about XY is correct?

A An atom of X has lost at least one electron to form a positive ion

B Both X and Y share a pair of electrons

C Element X is also a non-metal

D XY will not conduct electricity when liquid

Question 3 Which statement about chlorine atoms and chloride ions is correct?

A They are both isotopes of chlorine

B They undergo the same chemical reactions

C They have the same number of protons

D They have the same physical properties

Question 4 After acidification with dilute nitric acid, a colourless solution of X reacts with aqueous silver nitrate to give a white precipitate What could X be?

A calcium iodide B copper(II) chloride

C lead(II) iodide D sodium chloride Question 5 Which conditions will give the highest rate of diffusion of a gas?

Molecular of gas temperature

Question 6 Diamond and graphite are two different forms of the element carbon They

each have different uses Which row is correct?

Use

To cur glass As an electrode As a lubricant

Question 7 What is the number of shared pairs of electrons in an ammonia molecule?

A 3 B 4 C 5 D 6 Question 8 Powdered calcium carbonate reacts with dilute hydrochloric acid to produce

calcium chloride, water and carbon dioxide What is the correct ionic equation, including state symbols, for this reaction?

A CaCO3(s) + 2HCl (aq) CaCl 2(aq) + H2O(l) + CO2(g)

B Ca2+(aq) + CO32–(aq) + 2H+(aq) Ca2+(aq) + H2O(l) + CO2(g)

C CO32–(aq) + 2H+(aq) H2O(l) + CO2(g)

D CaCO3(s) + 2H+(aq) Ca2+(aq) + H2O(l) + CO2(g)

Question 9 In a volumetric experiment, 25.0cm3 of 0.100 mol / dm3 sodium hydroxide reacts exactly with 20.0 cm3 of sulfuric acid

2NaOH + H2SO4 → Na2SO4 + 2H2O What is the concentration of the sulfuric acid?

A 0.0625 mol /dm3 B 0.0800 mol /dm3

C 0.125 mol /dm3 D 0.250 mol /dm3Question 10 Which negative ions are present in aqueous copper(II) sulfate?

A copper(II) ions and hydrogen ions B copper(II) ions only

C sulfate ions and hydroxide ions D sulfate ions only Question 11 Some students wrote three statements about the bonding in a molecule of

ammonia, NH3 (1) A nitrogen atom has three outer electrons so all outer electrons are involved in bonding

(2) A nitrogen atom has five outer electrons so two outer electrons are not involved in bonding

(3) A nitrogen atom shares electrons with each of three hydrogen atoms

Which statements about the bonding in ammonia are correct?

A 1 and 3 B 1 only C 2 and 3 D 2 only

Question 12 What is the total number of valence electrons in the S4O6

2˗

ion?

A 58 B 60 C 62 D 82

Question 13 Gas X turns acidified potassium manganate(VII) from purple to colourless

Gas Y turns aqueous potassium iodide from colourless to brown

What do these observations show about gas X and gas Y?

Gas X Gas Y

A Oxidising agent Oxidising agent

B Oxidising agent Reducing agent

C Reducing agent Oxidising agent

D Reducing agent Reducing agent

Question 14 What is the best method to prepare a pure sample of copper(II) sulfate?

A Add copper to aqueous zinc sulfate

B Add copper to dilute sulfuric acid

C Add copper(II) carbonate to aqueous sodium sulfate

D Add copper(II) oxide to dilute sulfuric acid

Question 15 What is the percentage by mass of nitrogen in ammonium nitrate, NH4NO3?

A 17.5 B 22.2 C 33.3 D 35.0 Question 16 The solubility of KClO3 at several temperatures is shown in the accompanying diagram

A student mixes 10.0 g of KClO3 with 45.0 g of H2O and stirs it for a long time at

60 ˚C until the solution is completely clear then allows it to cool slowly to 20 ˚C where it remains clear Which statement about the final clear mixture at 20 ˚C is correct?

A It is a saturated solution

B It is an unsaturated solution and can be made saturated by decreasing the temperature

C It is an unsaturated solution and can be made saturated by increasing the temperature

A hydrated MgCl2 molecules

B hydrated Mg2+ ions and hydrated Cl– ions

C hydrated Mg2+ ions and hydrated Cl22– ions

D hydrated Mg atoms and hydrated Cl2 molecules

Question 19 Some atmospheric pollutants are listed

(1) sulfur dioxide (2) methane (3) nitrogen dioxide (4) unburned hydrocarbons Which substances could be removed by reacting with calcium hydroxide?

A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4 Question 20 River water contains many impurities Which process alone can produce

pure water from river water?

A adding chlorine B Distillation C Filtering D passing through carbon Question 21 Three experiments are carried out in which the same mass of magnesium is

reacted with the same volume of dilute sulfuric acid at room temperature The magnesium is in excess

experiment 1: Large pieces of magnesium are used

experiment 2: Small pieces of magnesium are used

experiment 3: Large pieces of magnesium are used but the concentration of the acid is

increased Graphs of the results are shown

Which row is correct?

experiment 1 experiment 2 experiment 3

Which ion is present in solution X?

A Al3+ B Ca2+ C Cu2+ D Zn2+Question 23 Which diagram shows the arrangement of particles inside a balloon

containing a mixture of the gases nitrogen and oxygen?

A 1 and 2 only B 1 and 3 only C 1 and 4 only D 1,2 and 4

Question 25 Which change always occurs when a metal atom is oxidised?

A It becomes positively charged B It combines with oxygen

C It gains an electron D It gains a proton Question 26 The total number of electrons in one atom of element Q is 17 and in one

atom of element R is 19 Which statement about elements Q and R is correct?

A Q and R react together to form a covalent compound

B Q forms positive ions

C R has more outer shell electrons than Q

D R is more metallic than Q

Question 27 Octane, C8H18, is a hydrocarbon that undergoes combustion in a petrol

engine

.W C8H18 + X O2  Y CO2 + Z H2O Which row shows the figures needed to balance the equation?

as the temperature of the solution increases?

1 CH4 2 NaBr 3 CO2 4 Glucose, C6H12O6 5 CuSO4

A 4 only B 1 and 3 C 1 and 4 D 5 only

Question 30 The table shows some properties of four metal chlorides Which row is

magnesium chloride?

Colour Solubility in water Method of preparation

Question 31 A lump of element X can be cut by a knife During its reaction with water,

X floats and melts What is X?

A calcium B copper C magnesium D potassium Question 32 In two experiments, 1 and 2, an excess of powdered calcium carbonate was

reacted in a flask with dilute hydrochloric acid

In experiment 1, the carbon dioxide evolved was collected and the volume of gas measured at regular intervals

In experiment 2, the mass of the flask and its contents was measured at regular intervals

The results of both experiments were plotted on graphs

Which graphs correctly show the results of these two experiments?

Question 33 Iron(II) ions react with chlorine

Which statement about this reaction is correct?

A Chlorine is reduced by iron(II) ions B Chlorine is the reducing agent

C Iron(II) ions are reduced by chlorine D Iron(II) ions are the oxidising agent

Question 34 Element Z combines with sodium to form the compound Na2 Z

The positions of four elements are shown on the outline of part of the Periodic Table

Which is element Z?

A A B B C C D D Question 35 The table shows the observations made when an aqueous solution of salt Z

has different reagents added to it

What is Z?

A copper(II) chloride B copper(II) sulfate

C iron(II) chloride D iron(II) sulfate

II PART II (3.0 points)

Write the solutions to the following questions in the provided space on your anwer sheet

Question 1

a) Balance the following equation:

P4O10(s) + H2O(l) → H3PO4(aq) b) When 4.585 g of P4O10 reacts with water to produce 100 mL of H3PO4 solution, what concentration of H3PO4 (in mol L-1) is this solution?

c) An aliquot of this H3PO4 solution is titrated with NaOH with using thymolphthalein as

an indicator 23.03 mL of 1.122 mol L-1 NaOH are required What chemical amount of NaOH is required? Express your answer in mol or mmol

d) If the aliquot of H3PO4 solution had a volume of 20.00 mL, how many moles of NaOH are required per mole of H3PO4?

Question 2 Some copper (ll) sulphate pentahydrate (CuSO4 5H2O), was heated at 120

How many molecules of water of crystalization were lost?

Question 3.The concentration of a saturated solution of calcium chloride in water at 0°C

is 60.93 g/100 mL, the density of this solution is 1.366 g mL-1 and the density of water at 0°C is 1.000 g

mL-1.What mass of calcium chloride hexahydrate (CaCl2·6H2O) needs to be added to

100 mL of water to make a saturated solution? (Hint: consider the water present in the added solid.)

a) P4O10(s) + 6H2O(l) → 4H3PO4(aq) b) mole of P4O10 is 4.585/284= 0.016 mol

P4O10(s) + 6H2O(l) → 4H3PO4(aq) 0.016 → 0.064 mol

→The concentration of H3PO4 (in mol L-1) is this solution: 0.064/0.1= 0.64 mol.L-1c) mole of NaOH is 0.02303 x 1.122 = 0.02584 mol

→ mass of NaOH is required: 0.02584 x 40 = 1.0336 (g) d) mole H3PO4 is: 0.64 x 0.02 = 0.0128 mol

We have

3 4

0.02584

2.018 20.0128

NaOH

H PO

n

→ 2 moles of NaOH are required per mole of H3PO4

H3PO4 + 2NaOH → Na2HPO4 + H2O

Let the mole of CaCl2.6H2O be a

→ mass of CaCl2 is: 111a (g)

→ mass of H2O in CaCl2.6H2O is: 18x6a = 108a (g)

→ mass of solution is 219a + 100 (g)

We have, mass of 100ml solution is 1.366x100 = 136.6 (g)

In 136.6 (g) of solution has 60.93 (g) of CaCl2

In 219+100 (g) of solution has 111a (g) CaCl2

→ 136.6 60.93

ĐỀ ÔN TẬP SỐ 3

I PART 1 (7.0 points) Question 1 Which of the following molecules contains 36.86% nitrogen by mass?

A NO B N2O C N2O3 D N2O4

Question 2 Which of the following compounds exists as linear molecules at room

temperature and pressure?

A CO2 B SO2 C NaCl D OF2

Question 3 Which of the following species contains 21 neutrons and 19 electrons?

A B C D

Question 4 Which of the following substances has the highest boiling point?

A water B nitric acid C hydrogen chloride D sodium chloride Question 5 When E10 fuel is combusted, it involves the combustion of organic

compounds ethanol and octane, as shown in the following chemical equations:

C2H5OH + 3 O2 → 2 CO2 + 3 H2O 2C8H18 + 25 O2 → 16 CO2 + 18 H2O When 1.00 g of ethanol and 1.00 g of octane are combusted in excess oxygen, what is the total volume of CO2 produced from the combustion, measured at 25 °C and 100 kPa?

(Molar volume of ideal gas at 25 °C and 100 kPa = 24.79 L)

A 1.08 L B 2.58 L C 2.81 L D 3.68 L

Question 6 When the complex ion Cr(OH)63− is heated with hydrogen peroxide solution under alkaline conditions, it is oxidised to CrO42− through a redox reaction The relevant half equations are:

H2O2 + 2 e → 2 OH− Cr(OH)6

A 0.1 mol B 0.2 mol C 0.6 mol D 1.0 mol

Question 7 Five beakers (labelled 1 to 5) each contain 0.5 moles of silver nitrate,

dissolved in water Into each of these beakers is added a certain amount of a metal

chloride, also dissolved in water, as shown in the table below

Silver chloride precipitates from solution in all five beakers

Which two beakers contain the maximum mass of silver chloride precipitate?

A 1 and 4 B 2 and 3 C 2 and 4 D 3 and 5

Question 8 When solid zinc is added to a solution containing silver nitrate, solid silver

precipitates from solution, according to the following chemical equation:

2AgNO3(aq) + Zn(s) → Zn(NO3)2(aq) + 2Ag(s) Which of the following shows the relative changes in concentration of each species over time?

A decreases no change

Question 9 Elements W and X react to form an ionic compound W and X have 2 and 6

valence electrons respectively What is the formula of this compound formed from the reaction between W and X?

A W2X6 B WX3 C WX D W3X

Question 10 A mass fraction of 1 part per million (ppm) is equivalent to a 1 g of solute

per million grams of solution (i.e solute + solvent), or 1 mg of solute per kg of solution

A solution is made by dissolving 358.4 mg of iodine in 0.2500 L of ethanol (the density

of ethanol is 0.7893 kg L −1) What is the mass fraction of iodine in this solution, expressed in ppm?

A 1130 ppm B 1132 ppm C 1434 ppm D 1816 ppm

Question 11 Which of the following is the next most abundant carbon dioxide

isotopologue having a relative molecular mass of 47?

A 11C18O18O B 12C16O17O C 12C17O18O D 13C17O17O

Question 12 A chemist is trying to determine the mass percentage of sulfate ions in a

fertiliser They know that the fertiliser contains only three anions: nitrate, carbonate and sulfate

The chemist decides to dissolve 4.000 g of fertiliser in water and add barium nitrate solution (this precipitates BaCO3 and BaSO4) They record that exactly 40.00 mL of 1.000 M barium nitrate solution was required for precipitation to be complete

The chemist prepares a second aqueous solution containing 4.000 g of the fertiliser and adds hydrochloric acid to it (this reacts with the CO3

A NaHCO3 B NaOH C NaNO3 D Na2SO4

Question 14 Nitric oxide (NO) reacts completely with oxygen to form nitrogen dioxide

according to the following balanced chemical equation:

2 NO(g) + O2(g) → 2 NO2(g)

If 2 L of NO and 1 L of O2 are reacted in a balloon, what will be the final volume of the balloon after the reaction is complete, assuming that the temperature and pressure are unchanged?

A 1.0 L B 2.0 L C 2.5 L D 3.0 L

Question 15 Calcium hydroxide (Ca(OH)2) is sparingly soluble in water, with a solubility of 1.73 g/L at 20 °C If 0.400 g of calcium hydroxide is placed in 200 mL of water at 20°C, what mass of calcium hydroxide will remain undissolved?

A 0.027 g B 0.054 g C 0.173 g D 0.346 g

Question 16 Phosphoric acid is a triprotic acid What mass of Ca(OH)2 would be

required to neutralise 100 mL of a 1 mol L−1 solution of phosphoric acid (H3PO4)?

A 3.7 g B 4.9 g C 7.4 g D 11.1 g

Question 17 Acid number is a commonly used metric in the paint industry It is defined

as the mass (mg) of potassium hydroxide required to completely neutralise the acid in 1 g

of paint A paint has an acid number of 185 What volume of 0.100 M KOH is required to completely neutralise 0.5 g of that paint?

A 1.65 mL B 3.30 mL C 16.5 mL D 18.5 mL Question 18 Consider four elements: calcium, oxygen, potassium and sulfur What

would be the correct order if they were arranged according to increasing electronegativity?

A Calcium < oxygen < potassium < sulfur B Calcium < potassium < sulfur < oxygen

C Oxygen < sulfur < potassium < calcium D Potassium < calcium < sulfur < oxygen

Question 19 Aqueous Fe2+ ions are readily oxidised to Fe3+ ions by oxygen gas in acidic solutions Consider the following relevant reduction half equations:

Fe2+(aq) →Fe3+(aq) + e 4H+ (aq) + O2(g) + 4e → 2H2O(l) What chemical amount (in mol) of H2O would be produced from the reaction of 2 mol of

Fe2+ with excess oxygen under acidic conditions?

A 1 mol B 2 mol C 4 mol D 8 mol

Question 20 Which of the following elements is a solid at room temperature?

A I2 B F2 C Cl2 D Br2

Question 21 2.00 g of a mixture containing NaNO3 and NaCl was dissolved in 250 mL

of water This solution was then titrated against 0.050 mol L–1 AgNO3, requiring 20.00

mL to fully precipitate the chloride ions as silver chloride What was the percentage by mass of NaCl in the sample?

A 1.77% B 2.92% C 5.84% D 7.17%

Question 22 A solid sample of calcium carbonate was placed into a solution of

hydrochloric acid Which of the following options shows the correct change in concentration of each species over time, as the reaction proceeds?

CaCO3 (s) + 2 HCl (aq)  H2O(l) + CO2 (g) + CaCl2

Question 23 A chemist wishes to make a fertiliser solution containing ions that will act

as a source of nitrogen, phosphorus and potassium Which one of the following mixtures

of solids will completely dissolve to give such a solution?

Question 24 A sample of water from a stream was analysed for the presence of metal

ions The results of some tests on the water are recorded in the table

Which metal is most likely to be present in the water?

A Ba2+ B Mg2+ C Cu2+ D Fe3+

Question 25 Sodium thiosulfate (Na2S2O3) reacts with hydrochloric acid according to

the following chemical equation:

Na2S2O3(aq) + 2HCl(aq) → 2NaCl(aq) + S(s) + SO2(g) + H2O(l) Solutions of sodium thiosulfate and hydrochloric acid were mixed and the volume of sulfur dioxide gas produced (at a pressure of 100 kPa) was recorded as a function of time The experiment was first performed at 25 °C and then repeated at temperature of 0°C Which of the following graphs show the results of these two experiments?

A B

C D

Question 26 Nitrogen dioxide (NO2) dimerises to form N2O4, as represented by the equilibrium reaction: 2 NO2(g) ⇌ N2O4(g) ∆H < 0

The following graph depicts the concentration of NO2 and N2O4 gases in a closed reaction vessel

At t = 10 s, the equilibrium between the two species is disrupted, and a new equilibrium

is reached

At t = 20 Which one of the following disruptions at t = 10 would be consistent with the graph?

A Addition of only N2O4 to the reaction vessel

B Addition of only NO2 to the reaction vessel

C Decrease in volume of the reaction vessel

D Increase in temperature inside reaction vessel

Question 27 What is the concentration (in mol L–1 ) of Na+ ions in a solution prepared

by diluting 250.0 mL of 0.550 mol L–1 Na2SO4 to 1250 mL?

A 0.110 mol L–1 B 0.138 mol L–1 C 0.220 mol L–1 D 0.275 mol L–1

Question 28 Which compound contains the highest percentage by mass of magnesium

(Mg)?

A MgNH4PO4 B Mg(H2PO4)2 C Mg2P4O7 D Mg3(PO4)2

Question 29 A student dissolves solid calcium carbonate in an excess of 0.01 mol L–1

nitric acid while stirring, and is looking for ways to make this reaction faster Which of the following actions would increase the rate of reaction?

A Adding distilled water to the solution while stirring

B Cooling the nitric acid before adding the calcium carbonate

C Decreasing the concentration of nitric acid

D Heating the nitric acid before adding the calcium carbonate

Question 30 Which list below gives non-metals that can be found in their elemental

form in nature?

A neon, phosphorus, fluorine B helium, hydrogen, oxygen

C helium, carbon, fluorine D nitrogen, chlorine, sulfur

Question 31 powder copper was added to a solution of silver nitrate at standard

conditions Given that silver is a less reactive metal than copper, which of the following observations would be most likely?

A A blue precipitate forms on the silvery solid and the solution turns colourless

B The blue solid dissolves in the colourless solution and a silvery precipitate is formed

C The silvery solid dissolves and a blue precipitate forms; the blue colour of the solution fades

D.The reddish brown solid is disolved, a silvery precipitate appeared, the solution changed from colorless to blue

Question 32 25.00 mL of each of the following solutions is added to 20 g of solid

MgCO3 After the reactions are complete, which of the solutions will produce the largest volume of CO2 at room temperature and pressure?

A 1 mol L–1 H2SO4 B 2 mol L–1 HCl

C 2 mol L–1 HNO3 D 2 mol L–1 H2SO4

Question 33 How is the structure and bonding in diamond best described?

A covalent molecular B covalent network

C metallic D molecular

Question 34 Which of these pairs of compounds could be separated on the basis of their

solubility in water?

A AgNO3 và CaBr2 B PbCO3 và CaCO3

C SiO2 và BaSO4 D ZnSO4 và AgCl Question 35 In which one of the following pairs is the radius of the second atom greater

than that of the first?

Question 2 You are given a 1.50-g mixture of sodium nitrate and sodium chloride You

dissolve this mixture into 100 mL of water and then add an excess of 0.500 M silver

nitrate solution You produce a white solid, which you then collect, dry, and measure

The white solid has a mass of 0.641 g

a If you had an extremely magnified view of the solution (to the atomic-molecular

level), list the species you would see (include charges, if any)

b Write the balanced net ionic equation for the reaction that produces the solid Include

phases and charges

c Calculate the percent sodium chloride in the original unknown mixture Question 3: To determine the molar mass of unknown metal, M, a student reacts iodine

with an exess of the metal to form the water- soluble compound MI2, as represented by the equation above

M + I2 → MI2 The reation proceeds until all of I2 is consumed The MI2(aq) solution is quantitatively collected and heated to remove the water, and the product is dried and weighed to constant mass The experimental steps are represented below, followed by a data table

a) Given that the metal M is in excess, caculate the number of moles of I2 that reacted b) Caculate the molar mass of the unknown metal M

a) Write the balanced net ionic equation for the precipitation reaction

Ba2+ (aq) + SO42- (aq)  BaSO4(s) b) precipitate formed is BaSO4

Mass of precipitate is 1.136-0.764 = 0.372 (g)

 The number of moles of precipitate formed: 0.372/233 = 1.6x10-3

mol c) number of moles of Ba(NO3)2 is: 0.200x0,02 = 0.004 (mol)

 number of moles of Ba2+

= 0.004 mol Because, number of moles of Ba2+ > number of moles of BaSO4

- Volume of 0.1 M CuSO4 (aq) needed: 0.0025/0.1 = 0.025 L = 25 ml

 We pour 25ml of 0.1M CuSO4 into graduated cylinder, then we add H2O until 50ml and stir

Question 2

Dissociation equations of substances NaNO3  Na+ + NO3-

NaCl  Na+ + ClAgNO3  Ag+

-+ NO3- a) If we had an extremely magnified view of the solution (to the atomic-molecular level),

we would see: Na+ , NO3

, Cl-, Ag+b) Write the balanced net ionic equation for the reaction that produces the solid

Ag+ (aq) + Cl- (aq)  AgCl(s)

Let the number of mole of NaCl be y Mass of initial mixture : 85x + 58.5y = 1.5 (1)

Ag+ (aq) + Cl- (aq)  AgCl(s)

y y Mass of precipitate 143.5y = 0.641 (2) From (1) to (2) , x = 0.0146 mol= number mol of NaNO3

y = 4.467.10-3 = number mol of NaCl  The percent sodium chloride in the original unknown mixture:

M + I2 → MI2

We have:

Number of moles of I2 = Number of moles of M = 0.004023 mol Mass of M that reacted = 1.284 g MI2 – 1.021 g I2 = 0.263 g M Molar mass of M = 0.263 65.4 /

0.004023 g mol

ĐỀ ÔN TẬP SỐ 4

I PART 1 (7.0 points) Question 1 Benzene, C6H6, reacts with oxygen, O2, to form CO2 and H2O How much

O2 is required for the complete combustion of 1.0 mol C6H6?

A 6.0 mol B 7.5 mol C 9.0 mol D 12 mol

Question 2 A 10.00 g sample of a soluble barium salt is treated with an excess of

sodium sulfate to precipitate 11.21 g BaSO4 (M = 233.4) Which barium salt is it?

A Silver nitrate is the limiting reactant and calcium nitrate precipitates

B Silver nitrate is the limiting reactant and silver chloride precipitates

C Calcium chloride is the limiting reactant and calcium nitrate precipitates

D Calcium chloride is the limiting reactant and silver chloride precipitates

Question 5 Which calcium compound is not appreciably more soluble in 0.1 M

hydrochloric acid than it is in pure water?

A Limestone, CaCO3 B Slaked lime, Ca(OH)2

C Gypsum, CaSO4 • 2 H2O D Hydroxyapatite, Ca5(OH)(PO4)3

Question 6 Which metal reacts most vigorously with water at 25 °C?

A Na B Mg C K D Ca

Question 7 Each of the following forms a colored aqueous solution EXCEPT

A Cr(NO3)3 B Fe(NO3)3 C Cu(NO3)2 D Zn(NO3)2

Question 8 A student wishes to measure 37 mL of a liquid Which apparatus would be

most suitable?

A 50 mL graduated cylinder B 50 mL florence flask

C 50 mL beaker D 50 mL Erlenmeyer flask

Question 9 A 2.0 mL sample of a colorless solution, when treated with a few drops of 2

M hydrochloric acid, forms a white precipitate which dissolves when the solution is heated to boiling The original solution could have contained which of the following cations?

I 0.1 M Ag+ II 0.1 M Pb2+

A.I only B II only C Either I or II D Neither I nor II

Question 10 Which of the following would lead to an increase in the vapor pressure of

a liquid?

I Increasing the temperature II Adding a nonvolatile solute

A I only B II only C Both I and II D Neither I nor II

Question 11 A student is separating CHCl3 (bp = 61 °C) from CHCl2CHCl2 (bp = 146

°C) by distillation She has just begun to collect the first distillate in the receiving flask

At what position in the apparatus will the temperature be 61°C?

A A B B C C D.D

Question 12 A 3.0 L sample of helium gas is stored in a rigid, sealed container at 25 °C

and 1.0 atm pressure The temperature is increased to 125 °C What is the new pressure

of the gas?

A 0.20 atm B 0.75 atm C 1.3 atm D 5.0 atm

Question 13 Diamond is an example of what kind of solid?

A Ionic B Metallic C Molecular D Network covalent

Question 14 The cubic unit cell of a perovskite structure containing atoms of types A,

B, and C is illustrated below What is the empirical formula of this substance?

A ABC B ABC3 C AB4C6 /D AB8C12

Question 15 For the reaction 5O2(g) + 4 NH3(g)  4 NO(g) + 6 H2O(g)

if NH3 is being consumed at a rate of 0.50 M•s –1 , at what rate is H2O being formed?

I Higher water solubility II Higher melting points

A I only B II only C Both I and II D Neither I nor II Question 18 What is the relationship between the two compounds below?

CH3CH2CH(CH3)CH2CH3 CH3CH2CH2CH(CH3)CH3

A Identical B Stereoisomers

C Geometric isomers D Structural isomers

Question 19 Which compound contains the highest percentage of magnesium by mass?

A MgNH4PO4 B Mg(H2PO4)2 C Mg2P4O7 D Mg3(PO4)2

Question 20 In the diagram above the paired open spheres represent H2 molecules and the paired solid spheres represent N2 molecules When the molecules in the box react to form the maximum possible amount of ammonia (NH3) molecules, what is the limiting reactant and how many molecules of NH3 can be formed?

A N2 is limiting 5 molecules of NH3 can be formed

B N2 is limiting 10 molecules of NH3 can be formed

C H2 is limiting 8 molecules of NH3 can be formed

D H2 is limiting.12 molecules of NH3 can be formed

Question 21 Vanillin, C8H8O3 (M = 152 g/mol), is the molecule responsible for the vanilla flavor in food How many oxygen atoms are present in a 45.0 mg sample of vanillin?

A neon, phosphorus, fluorine B helium, hydrogen, iodine

C nitrogen, oxygen, sulfur D oxygen, chlorine, phosphorus

Question 26 Which one of the following cannot act as an oxidizing agent?

Question 28 Which method(s) can be used to determine the concentration of HNO3 in

an aqueous solution of nitric acid?

I titration with a standard base

II titration with a standard oxidizing agent III precipitation with Ag+

A I only B III only

C I and II only D I, II, and III

Question 29 What type of solid is silicon carbide, SiC?

A ionic B metallic

C molecular D network covalent

Question 30 A device used to test alcohol in the bloodstream uses the reaction

2K2Cr2O7(aq) + 8H2SO4(aq) + 3CH3CH2OH(aq)  2Cr2(SO4)3(aq) + 2K2SO4(aq) + 3CH3COOH(aq) + 11H2O

If the rate of disappearance of K2Cr2O7 is 1.24 M/min what is the rate of disappearance of

A I only B III only

C I, II, and III D None of these

Question 32 What is the oxidation number of As in the compound K(NH4)2AsO4•6H2O?

is balanced correctly with the smallest whole number coefficients, what is the coefficient for H2O?

B the same molar mass but different atoms in their composition

C the same physical properties but different chemical properties

D different isotopes in their structures

II PART 2 (3.0 points) Question 1 Phosphoric acid can be manufactured according to the following reaction:

Ca3(PO4)2 + SiO2 + C + O2 + 3 H2O CaSiO3 + CO2 + H3PO4

If equal masses of calcium phosphate (M = 310.) and silica (M = 60.0) are reacted with excess carbon, oxygen, and water to produce 1.00 x103 kg phosphoric acid (M = 98.0), what mass of calcium phosphate was used, assuming 100% yield?

Question 2 A certain gas A is a component of atmospheric air and plays an important

role in the photosynthesis of plants A strip of magnesium burns in A to produce a grey mixture of a white substance B and a black substance C Know that B is insoluble in the bases; C are virtually insoluble in dilute acids and bases Combustion of C in oxygen yields A When magnesium is burned in gas D, which is another component of atmospheric air, a white substance E is formed The latter dissolves rapidly in acids and decomposes in water to produce gas F with a characteristic pungent odor

a) Identify compounds A through F

b) Write the chemical equations to represent the transformations of these compounds c) The interaction of A with F is a commercial method of production of a certain valuable fertilizer Name this fertilizer and write the chemical equation for its production

Question 3 A 1.92 L sample (at STP) of a gaseous mixture of hydrocarbons that is

12.6% elemental hydrogen (by mass) was burned in an excess of oxygen The volatile combustion products were dried and bubbled through 400 mL of a 4.82% (by mass) NaOH solution with a density of 1.05 g/cm3

a) Calculate the initial mass of the hydrocarbon mixture given that its specific gravity relative to nitrogen is 2.27

b) What volume is occupied by the resulting carbon dioxide at STP?

c) Determine the qualitative and quantitative composition of the solution obtained by bubbling the carbon dioxide gas through the NaOH solution

m

→ silica is residual Accrording the reaction Number mole of calxium phosphate is 5102.04 mol

→ mass of calcium phosphate was used = 5102.04x310 = 1581632.4g

Mg3N2 + 6H2O → 3Mg(OH)2 + 2NH3 c) The interaction of A with F is a commercial method of production of a certain valuable fertilizer

2NH3 + CO2 P t,0C (H2N)2CO + H2O

Urea fertilizer

Question 3

a) Calculate the average molar mass of the mixture: 2.27 x 28 = 63.56 g/mol Calculate the initial mass of the mixture: 63.56 x 1.92 / 22.4 = 5.448 grams

b) The mass of elemental carbon: 5.448 x (100 - 12.6) / 100 = 4.762 grams

Mole of C = mole of CO2 = 4.762 / 12 = 0.398 mole The volumes of CO2 = n.R.T / P = 0.398 x 0.082 x (20 + 273) / 1 = 9.562 L

c) Moles of NaOH: 400 x 1.05 x 4.82 / (100 x 40) = 0.506 mol

Because 1 < n(NaOH) / n(CO2) = 0.506 / 0.398 < 2 so we have two salts: Na2CO3 and NaHCO3

n(Na2CO3) = 0.506 – 0.398 = 0.108 mol

n(Na2CO3) = n(NaOH) - 2 x n(Na2CO3) = 0.506 – 2 x 0.108 = 0.290 mol

The mass of the solution = 0.398 x 44 + 400 x 1.05 = 437.512 grams

The mass percent of Na2CO3 is 0.108 x 106 / 437.512 = 0.0262 = 2.62%

The mass percent of NaHCO3 is 0.290 x 84 / 437.512 = 0.0557 = 5.57%

ĐỀ ÔN TẬP SỐ 5

I PART 1 (7.0 points) Question 1 Greenhouse gas molecules absorb ultraviolet rays from the sun Absorbing

energy from these rays causes the covalent bonds in gas molecules to vibrate, compress

or twist For this to happen each gas molecule must have at least three nuclei Which of the following gases is present in the atmosphere but does not cause the greenhouse effect?

A nitrogen monoxide B methane C ozone D Steam

Question 2 Which of the following statements is true about the modern periodic table?

A The periodic table only lists the elements that naturally exist on earth

B The elements in the periodic table are arranged in order of increasing atomic mass

C Elements in a period have similar sizes and similar chemical properties

D Elements in a group have the same number of outermost electrons

Question 3 One study showed that enamel erosion is limited if teeth are exposed to

fluoride ions Most toothpastes contain fluoride salts such as tin fluoride, sodium fluoride On the packaging of a common toothpaste, it shows that the toothpaste contains 0.41% tin fluoride by mass If a tube of the above toothpaste contains 150 grams of cream, what is the mass of the fluoride ion in that tube of toothpaste?

A 0,28 B 0,17 C 0,15 D 0,07

Question 4 Aqueous solutions of which of the following pairs of compounds will not

react together to form a precipitate?

A silver nitrate and ammonium iodide

B sodium hydroxide and copper(II) sulfate

C silver nitrate and barium chloride

D sodium hydroxide and ammonium chloride Question 5 The correct name for an aqueous solution of HCl is

A chloric acid B chlorous acid

C hydrochloric acid D hydrogen chloride

Question 6 Atom X has 9 protons, 10 neutrons and 9 electrons Atom Y has 9 protons, 9

neutrons and 9 electrons Which of the following statements best describes how Atom X and Atom Y are related?

A X and Y are isotopes of the same element

B X is an ion and Y is a neutral atom

C X and Y are different elements

D X is neon and Y is fluorine

Question 7 Which of the following pairs of atoms is least likely to form a compound?

A Potassium (K) and Iodine (I) B Calcium (Ca) and Chlorine (Cl)

C Iron (Fe) and Sulfur (S) D Neon (Ne) and Argon (Ar)

Question 8 The reason salt crystals, such as KCl, hold together so well is because the

cations are strongly attracted to

A neighboring cations B the protons in the neighboring nucleus

C free electrons in crystals D neighboring anions

Question 9 Bonding between two elements of equal electronegativity would be

A 100% covalent B primarily ionic

C 50% ionic D metallic in character

Question 10 Consider the four containers below

Which container contain only: mixture, compound, element?

Ion formed by a Ion formed by b Ion formed by c Ion formed by d

Question 15 One way to measure the concentration of a substance is through molality A

1 molal solution is defined as 1 mol of substance per 1 kg of the solvent used to make up the solution What is the molality of a solution made by dissolving 100 g of bromothymol blue (C27H28Br2O5S) in 1.00 L of ethanol on a winter‘s day at 10ºC? The density of ethanol at this temperature is 0.7979 kg L-1

A 0.100 mol kg–1 B 0.128 mol kg–1 C 0.160 mol kg–1 D 0.201 mol kg–1

Question 16 Which one of the following bonds is the most polar?

B The number of moles of product is equal to the number of moles of starting material

C The rate of the forward reaction is greater than the rate of the reverse reaction

D The rate of the forward reaction is equal to the rate of the reverse reaction

Question 20 How many electrons are transferred from 10 I– ions to 2 MnO4– ions in the following redox reaction?

2 MnO4– (aq) + 16 H+ (aq) + 10 I– (aq) → 2 Mn2+

(aq) + 5 I2(s) + 8 H2O(l)

A 2 B 5 C 8 D 10

Question 21 In which one of the following compounds does manganese exist in the

lowest oxidation state?

A Mn2O7 B Mn(CH3COO)2⋅4 H2O C KMnO4 D MnO2

Question 22 Pure water undergoes self-ionisation according to the equation:

2 H2O(l)  H3O+ (aq) + OH– (aq) The [H3O+ ] [OH– ] constant for the reaction is: 1.0 × 10–14 at 25°C and 5.5 × 10–13 at 100°C Which one of the following statements is correct?