] = 0.10 M by taking some NaOH and some trona (Na2CO3•NaHCO3•2H2O) and diluting with water to a final volume of 1.00 L. How much NaOH and trona are required?
Exercise 2. Hydrogen peroxide is a powerful oxidizing agent used in concentrated solution in rocket fuels and, in dilute solution, in hair bleach. An aqueous solution of H2O2 is 30% by mass and has a density of 1.11 g/mL. Calculate the:
a. mole fraction of H2O2 ( mole of solute/( mole slovent + mole of solute) b. molarity of the solution ( mole of solute per one liter of solution) Exercise 3. Consider the reaction
I2O5(g) + 5 CO(g) → 5 CO2(g) + I2(g)
a) 80.0 grams of iodine(V) oxide, I2O5, reacts with 28.0 grams of carbon monoxide, CO.
Determine the mass of iodine I2, which could be produced?
b) If, in the above situation, only 0.160 moles, of iodine, I2 was produced.
i) what mass of iodine was produced?
ĐÁP ÁN ĐỀ ÔN TẬP SỐ 19 I. PART 1 (7.0 points)
Câu Đ/án Câu Đ/án Câu Đ/án Câu Đ/án
1 C 11 B 21 A 31 B
2 C 12 C 22 C 32 B
3 B 13 C 23 B 33 D
4 B 14 A 24 B 34 A
5 D 15 B 25 D 35 A
6 B 16 C 26 C
7 A 17 B 27 D
8 B 18 D 28 A
9 A 19 C 29 C
10 C 20 B 30 A
II. PART 2 (3.0 points) Exercise 1.
Let mole of NaOH are required be a mol
Let mole of trona(Na2CO3•NaHCO3•2H2O) are requited be b mol We have electrolyte equations of the substances
NaOH → Na+ + OH- a → a → a
Na2CO3•NaHCO3•2H2O → 3Na+ + CO3
2- + HCO3 - b → 3b → b → b The net ionic equation between substances
OH- + HCO3-
→ CO32-
+ H2O a → a
In the after solution, we have
3
3 0.50 1.0 0.5 0.1 1.0 0.1
Na HCO
n a b x mol
n b a x mol
→ a = 0.05 mol ; b = 0.15 mol →0.05 mol NaOH, 0.15 mol trona Exercise 2.
a) Assume, we have 100 g of solution
→mass of H2O2 = 30%x100 = 30 g → mole of H2O2 = 30/34 = 0.88 mol
→mass of H2O2 = 100 – 30 = 70 g → mole of H2O2 = 70/18 = 3.88 mol
→ mole fraction of H2O2 = 0.88 0.18 0.88 3.89
b) volume of solution = 100/1.11 = 90.1mL=0.09L
→molarity of the solution= 0.88 9.78 0.09 M
Exercise 3.
Consider the reaction
I2O5(g) + 5 CO(g) → 5 CO2(g) + I2(g) a) mole of I2O5 = 80 0.24
127 2 16 5 mol
x x
mole of CO = 28 1.0
28 mol
We have ratio mole between CO and I2O5
1.0 4.17
0.24 <5 1
→ CO is limitting
→ nI2 = 1 1 0.2
5x mol→ the mass of iodine I2 = 0.2x254 = 50.8g
b) ) If, in the above situation, only 0.160 moles, of iodine, I2 was produced.
i) what mass of iodine was produced = 0.16x254 = 40.64g ii) percentage yield of iodine was produced =0.16 100 80%
0.2 x
ĐỀ ÔN TẬP SỐ 20 I. PART 1 (7.0 points)
Question 1. We can contains the concentrated, cool HNO3 solution in the tank made of what metal?
A. Copper, silver B. Copper, lead. C. Iron, aluminum. D. Copper, zinc.
Question 2. Identify substances (A) and (B) in the following sequence:
N2 + H (xt, t , p)2 o NH3 + O (Pt, t )2 o (A) + O2 (B) HNO3
A. (A) is NO, (B) is N2O5 B. (A) is N2, (B) is N2O5
C. (A) is NO, (B) is NO2. D. (A) is N2, (B) is NO2
Question 3. When the sample of molten sodium is added into the container of Cl2. The mass of salt obtained depends on time as follows:
Graph showing the dependence of mass on time
What is the maximum volume of Cl2 gas (at STP) reacted with sodium?
A. 5.6 liters. B.33.6 liters. C. 22.4 liters. D. 11.2 liters
Question 4. For diagram: (NH4)2SO4 + A NH4Cl + B NH4NO3
In diagram A, B respectively of substances:
A. HCl, HNO3 B. CaCl2, HNO3 C. BaCl2, AgNO3 D.HCl, NaNO3
Question 5: To identify phosphate ions (PO43-), the reagent is used
A. AgNO3 solution B. Limut paper C. NaOH solution D. BaCl2 solution Question 6: Choose the correct expression:
A. White Phosphorus is soluble in water and non-toxic.
B. White phosphorus is preserved by immersion in water.
C. White phosphorus activities less chemically than red phosphorus D. Red phosphorus can light green in the dark
Question 7: Which of the following statements is not correct when talking about phosphoric acid?
A. Phosphoric acid is a three-step acid. B. Phosphoric acid is medium acid C. phosphoric acid is very strong oxidation. D. Phosphoric acid causes limut turn red.
Question 8. Diamonds and graphite are two allotropes of carbon because A. has the same crystal lattice structure.
B. form of carbon element and have different physical properties.
C. have similar physics properties
D. have not similar chemistry properties
Question 9. For the following statements about the oxidation process (1) the process of reducing the oxidation number of the element.
(2) the process of increasing the oxidation number of the element.
(3) the process gives up electrons of reduction agent (4) the oxidation agent receives electron
The True statements are:
A. (1) and (3). B. (1) and (4). C. (3) and (4). D. (2) and (3).
Question 10. For the following chemical reaction is in equilibrium.
2SO2 (k) + O2 (k) 2SO3 (k).
As the temperature increases, mass ratio of a mixture gases with hydrogen is decreasing Which of the following statements true about balance
A. the reverse reaction is an exothermic reaction , balance shifted forward when temperature increases
B. the forward reaction is an exothermic reaction, balance shifted reverse as temperature increases
C. the forward reaction is an endothermic reaction, balance shifted in the reverse direction when temperature increases
D. the reverse reaction is an endothermic reaction, balance shifted forward when temperature increases
Question 11. Composition of elements in organic compounds are A. necessarily carbon, usually H, often O, N then halogen, S, P ...
B. consists of C, H and other elements.
C. includes all elements in the periodic table.
D. usually C, H often O, N, then to halogen, S, P.
Question 12. Range of substances that contain substances are isomers of each other?
A. C2H5OH, CH3OCH3. B. CH3OCH3, CH3CHO C. CH3CH2CH2OH, CH3CH2OH D. C4H10, C6H6
Question 13. Consider the following reactions:
(1) MnO2 (s) + HCl (con.) X (g) + ...
(2) Na2SO3 (aq) + H2SO4 (con.) Y (g) + ...
(3) NH4Cl (aq) + NaOH (aq) Z (g) + ...
(4) NaCl (s) + H2SO4 (con.) D (g) + ...
(5) FeS (s) + HCl (aq) E (g) + ...
How many gaseous products can react with NaOH in solution?
A. 2 B. 3 C. 4 D. 5
Question 14. A student studies a solution of X in an unlabelled jar and results in the following:
- X reacts with all three solutions: NaHSO4, Na2CO3 and AgNO3. - X does not react with all three solutions: NaOH, Ba(NO3)2, HNO3.
A. BaCl2. B. CuSO4. C. Mg(NO3)2 D. FeCl2. Question 15. An organic compound X contains 51% C, 9.4% H, 12% N, 27.3% O (by weight). The mass of X compare with air is 4.03. So the molecular formula of organic is: