English for chemistry student nguyen van dau chị hóa

Thus theory and experirnent reinforc-e eaih other' We rnusr gain some ins-ight into atomic structure to appreciate thebehavior of the atoms themselves as well as larger aggregates I of a

, 1 ( 1 t i 1 , ,/ 1 " t ' /

ror oror rnl€u

C u 6 n "E n g l i s h fo r s t u d e n t s of Ghemistry" dtlgc bi6n soan dua tr6n c5c

Muc dich bi6n soan c0a cuon s6ch ndy ld cung cdp kien thfc tidng Anh

c h u y 6 n n g d n h h 6 a h o c c h o sinh vien vd nhlng ngudi lam vi6c lien quan ddn

h 6 a h o c , ta o d i d u k i 6 n t h u d n loi hon cho ho khi doc c6c tdi lidu tieng Anh vd

c h u y d n n g d n h n a y D o v A y , tiep can chinh cOa cuon s6ch lir tap trung vdo ki

n d n g d o c h i d u , m 6 t s o d a c didm vdn phong khoa hoc vd c6c van dd ngfi ph6p

c h o s i n h v i 6 n p h 6 t tr i d n ki ning viet thong qua c6ch sfi dung tieng Anh dd ftrd

d i c h tr l t i e n g V i 6 t s a n g t i d n g Anh tuy chi chidm mdt phdn nh6 trong m6i don vi

c h u y d n n g L t ( d i c h ) n h r t n g c d u v 5 n n g 5 n , d o n g i 6 n

CA'u tric cia cu6'n sdch

C u d n s 6 c h n a y ddnh cho sinh vi6n hoc 6 giai doan hai, giai doan chuydn

h o c tr i n h (1 2 0 ti e t ) P h d n 1 gdm 8 unit, ph5n 2 g6m 9 unit vd cu6i m6i phdn d6u

c o b d i k i d m tr a d d t h a m khAo N6i dung chuydn ngdnh 6 phdn i bao trirm ch0

M 6 i u n i t g d m c 6 n h 0 n g muc chlnh sau:

- Reading

doc hidu, 6 phdn niry x6y dung c6c biri t6p, nhu tri toi c6u h6i, x6c dinh ! kidn

d 0 n g h a y s a i , h o d n t h i 6 n c 6 u , t l m t r J d d n g / n g u o c n g h i a P h d n R e a d i n g n h d m

d o c h i d u

- Grammar

Nhltng vdin dd ng0 ph6p xudit hien trong bai doc cu thd, hoac kiSn thfc

vAy, nghia cOa mot s6 trt d6i khi c6 tinh han htru, rdt xa la v6i nghia tieng Anh

D a i h o c Quoc gia He Ndi

1 Reading Text 1 Reading Text

A Comprehension Questions A Comprehension euestions

B True-False Statements B True-False Statements

C Sentence Completion C Contextual Reference

D Translation D Sentence Conrpletion

5 Supplementary Material 4 Supplementarl Ilaterial

A Further Reading A Further Reading

B Mathematic Section B Experimental Technique

C Laboratory Apparatus Important Terms

6 \'ocabulary S Vocabularv

a d j

a d v

AdjectiveAdverb

C o n j u n c t i o n

N o u n

past participlePrepositionSomebody

S o m e t h i n gVerb

PART I

G E N E R A L C H E M I S T R Y

1 i

In scientific terminology, matter is anything that occupies spaceand has mass (weight) Chemists group matter into several categoriesfor better identification In this unit we will seek to understand this -plassification of matter and learn how it relates to physical and, f c h e m i c a l c h a n g e s 4 l , v , v n \

J_

A11 matter lis either la pure substance or a mixture A puresubstance has a definite and constant composition; it has physical andchemical propertiet,r*l?yfhout Pure water is a pure substance It istgggg_9".]J-!Aphrtibles containing two hydrogen atoms and onercoxygen atom, that is, water molecule A mirture is a combination oftwo or more pure substances in which each substance retains its orvnidentity Alcohol and @d in a mixture Jhei

coexist as pure substances b ourJ.fEf",l

t l t t r

7 - , : { t ! ' ! u t } r4t A mixture mar'l be either lhomo_eeneousot

mired or thoroughlv intermingled

unrfornr cornposition Concrete is lcom

of ntatcrials (r arious types and size of stone and sand present with cement

in a non-uniform mixture) Homogeneous mixtures of at least two

- - - l - - - - ^ - - - - - - " I

:olrds dependin-e on the nature of the main component Any mixture,

r nc I ud r n s a sol ut ion, can Fp selrarated-.rrro.J ts components by physical

a c l i o l t \ i ii l t e r i n g b o i l i n g , )

\11\ture of alcohol and water is an example of liquid solution Air,.t ntr\turL- of gases is the most common gaseous solution The common.r.lirl ,.lLrtions are ullut,s' uniform mixture of two or more solid

The re are different types of pure substances Elements and.-r -l

: r'.;J ofla single kind of matter Thev cannot be sgparated into other,.r::-.:ie r iorm of matter by either physical or chemical methods Hydrogenerd tr\r sen for sample, are elements Altematively, compounds aresub>rancer formed when two or more elements bond chemically .,.,i Compounds aln'avs have a definite and constant composition; this means

l a ' \ r !

v '

Iher [co-n_!+inJ elements in fixed proportions Compounds cannot bereparat-ed into other components by physical method, but they can be.3uarilted into different elements or simpler compounds by chemical

\uatoms Water for erample consists of moiecules lmade up ofi two,hydrogen aroms bonded ro one oxygen atom Compo#a;;ail';I#oken

t

down into elements or simpler compounds by chemical methods whichusually require energy Their smallest subcomponents are molecules: ifvou break these molecules down to their constituent atoms, the compound

no longer exists ', {

Notes:

- In scientific terminology

- Occupy space and have mass (weight)

- Group matter into several categories

- Each substance retains its own identity

- They exist as thoroughly mixed discrete molecule

- Are described as solutions

- Is composed of a single kind of matter

- The basic buildine blocks of all matter

A C O M P R E H E N S I O N Q U E S T I O N S

Ansv'er the follov,i11g que sti ot1s :

1 What is the difference between a pure substance and a mixture?

2 What is the difference betrveen homogeneous and heterogeneousmixtures?

3 What is a solution defined as?

4 What is an allov defined as?

5 Why is water considered to be compound?

L U

B T R U E - F A L S E S T A T E M E N T SWrite "True" (T) or "False" (F) beside each fiotement according totlrc information from the text.

l Matter is anything that undergoes physical and chemical

changes

2 Either element or compound is a pure substance

3 Air is a homogeneous mixture while alloys are

heterogeneous mixtures

4 Concrete is a solid solution

5 A solution can be separated into its components by physical

actions

6 Being a pure substance, a compound cannot be separated

into other, simpler form of matter by either physical orchemical methods

1 An alloy is a mixture of tu'o or more solid substances in

which each substance retains its orvn identity

8 The smallest subcomponents of a compound are atoms

Q S E N T E N C E C O M P L E T I O NBased on the information fi'om the text, complete the followingsentences

1 Alcohol and water can be mixed

2 Alloy is a homogeneous mixture

3 Compounds are

-1 A pure substance may be either or

D T R A N S L A T I O NTranslctte the text into V ietnamese

1 6

THE OF-STRUCTUREThe o/-structure sometimes is used in expressions to describecharacteristics of a person or thing

Example: a student of big weight

a substance o[ great importance

a reaction of significance

a metal of no value

a compound of significant interest

These expressions can be rewritten as following:

Example: Oxygen is of great importance to humans

+ Oxygen is very important to humans

Meldeleev's discoveries are of great significance to modem science.+ Meldeleev's discoveries are significant to modem science

DESCRIBING QUALITIES OF MATERIALS

All materials (glass rvood rubber steel etc.) have variousproperties Solid materials ma1'be found in the follou'ing forms: powder,

c ry sta I s, Ji lirigs etc

Some solid materials and propefiies are given in the table below

Materials Adjectives used to describe qualitiesglass t r a n s p a r e n t o p a q u e , ' , I

wood combustible non-combustible

l 6

steel strong weak

paper fragile, flimsy sturdy 'l

concrete r i g i d I I floppy t/ , iporcelain (china), brittle r',1 r e s i l i e n t t i / r r ' i

Steel is a strong and rigicl ntaterial

We often want to modify statements about the properties ofmaterials Some words used to emphasize are extremely, verv, cluite,fairly, sl i ghtly, considerabl-v, etc.

For example: G/ass is ertremellt brittle

Some properties of liquids and fluids are listed in the table below

PROPERTIES OF MATERIALSBrittle = theY break easilYTough = theY don't break easilYHard = they are difficult to scratchSoft = they are easy to scratchFlexible - theY are easy to bendRigid - theY don't bend easilYInsoluble - they don't dissolve in liquidsSoluble - theY dissolve

Cornbustible = they burn easilYNon-combustible = they don't burnTransparent = vou can see through themOpaque = ]ou can't see through them and light doesn't pass throughTranslucent_youcan'tSeethroughthemandlightcanpassthrough

S m o o t h = t h e y d o n ' t p r o d u c e f r i c t i o n r v h e n r u b b e dRough - they produce friction rvhen rubbed

Miscible (liquids) = they can dissoive in each otherImmiscible (liquids) - they don't dissolve in each otherExercise 1

Comple.te the clescription of properties of pol)"sry'rene '

P o l y s t y r e n e i s a ' i ' l ' : " " ' ( l ) m a t e r i a l ' It s r i g i d i t y c a n b e adisadvantage since it is also .(2)' The brittleness of polystyrene can

be decreased by the addition of rubber, to make it """(3)' But thenatlrral fleribility of many other plastics makes them preferable for

c e r t a i n u s e s p a r t i c u l a r l y f o r a r t i c l e s , w h i c h m u s t w i t h s t a n d f r e q u e n t

f l e x i n g F o r e x a m p l e ' t h e c o v e r i n g f o r t h e w i r e f l e x e s o f e l e c t r i c a l g o o d si's generallv macle of polyethylene or PVC Notice that a "''"'""(4) cord

I

Exercise 2

Make sentetrces cctntput'irtg tlrc properties of the materittls basetl t,titlte follovin g prlmpt s

Example: Steel is much stronger than wood

1 glass/ fragile/ steel

2 paper/ flimsy/ wood

- 1 c o p p e r / d u c t i l e / i r o n

4 rubber/ rigid/ steel

5 polythene/ brittle/ material/ glass

6 porcelain/ resilient/ material/ plastic

7 copper/ good/ conductor/ lead

8 iron/ poor/ conductor/ aluminium

There are three (l) of matter: the gaseous, the liquidstate, and the solid state A gas is (2)of particles that are widelyseparated In fact, a gas will expand (3) any container; it has

no definite (4) or volume (5), particles of a liquid areclose together; a liquid has a definite volume (6) definiteshapc: it has taken on the shape of its container A solid consists of

.(7) that are close together and that often have a regular and (8) pattern of particle arrangement (crystalline) A solidhas both fired volume and (9) shape Attractive forces,which exist betu'een all particles, are strongest in solids and

( l 0 ) i n s a s e s

2 2

I Water tiquefy air to be a mixture

+ Air enters from the boiling solution

5 All gases can be

separated

at temperatures above -273 C

) r

(fiietni()n to the lt'ol'ds "all"

TRANSLATION

A' Translate tlrc follov'irtg sentettces

aliabove allafter all c't :all over

L

Alpha-rays have positive charges' beta-rays are negatively charged

*trit" gamma-rays have no charge at ull'

After all,the rays of the sun as a power can be put to work

without

rnuch costlY machinerY'

First of all, you have to know the most important chemical

laws

underlying these natural phenomena'

Att ofthis kinetrc energy may be used to do rvork as the

moving

object is slowed down to rest'

A// in the earth and the atmosphere is made up of atoms andmolecules

The life at other planets, if it exists at all' is not like ours'

There are acids which contain no oxygen at oll'

Iron in damp air becomes coated with rust which is a substance

not

at a// like iron

Hydrogen and chlorine are known to react together with explosive'iolence, if they are exposed to sunlight' but perfectly dry hydrogenand perfectly dry chlorine fail to reacr at all'

\il the sdnle.the first atomic energy stations were to be built awayfrorn the thickly-populated areas'

B.Tr'rtitslate tlte follov'ing sentences into English'

l Tinh chiit ld dac tinh cua vAt chat'

2 Tinh chat hoac l)r vAt li holc ld hoii hoc'

3 V A t c h A t t d n t a i o b a t r a n g t h 6 i ' r i n ' l 6 n g v h k h i '

4 H6n hqp Id su ket hqp cila hai hoac hon hai chdt tinh khiet'

5 H6n hqp di thti c6 thdnh phdn khong ddng nhat.

6 Trong mOt h6n hop dong the cdc phdn ru cua n6 duoc tron deu

7 NguyOn t6 khong thd chuydn hod th)nh dang vAt chat don giinhon bang bdt ki phan rmg hoii hoc ndo

8 Chat tinh khiet c6 thO lh nguy€n t6 hay hqp chat

9 Nu6c gdm cdc phAn tu duoc tao thinh tir hai nguyOn tri hidro vhm6t nguy€n tir oxi

1 0 T h 6 p lh m o t d u n g d i c h r d n c u a m 6 t v h i k i m l o a i v d c a c b o ntrong sit

SUPPLEMENTARY MATERIAL

F U R T H E R R E A D I N G

Read the following passage and translate it into Vietnamese

MATTER AND PROPERTIESEverything on earth- air, food, water, our own bodies- is made up ofmatter Matter is therefore such a general term that we must classifydifferent types of matter to discuss it

Broadly speaking, matter may be either homogeneous (uniform) orhete-rogereous (non-uniform) Homogeneous matter may be eithersolutions (mixtures) or pure substances (elements or compounds).Solutions may be solids (such as alloys), liquids (nonaqueous or aqueous),

or gases In fact, any type of matter exists in one of these three states

Each state of matter has specific characteristics Gases, fbrexample have low densities are highly compressible and rnix readily.Liquid molecules are less orderly than solid molecules and more orderlythan gas molecules Similarly, liquids are denser than gases but not asdense as solids Solids may be highly organized crystal structures ordisordered amorphous structures Crystalline solids may be metallic.molecular, ionic, or macromolecular, each is characterized by diffcrcntpropefiies Solids are the most dense and the least compressible oi thethree states of matter

2 i

M A T H E M A T I C S E C T I O N I

Arithmetical operations , i

Addition In spoken English 2 + 2 = ,l is "Tv,o plus tv,o ecptalsforu'" or "Tv,o plus ttt,o isfour " The result of this operation is called thesruz Thus, if two is added to two, the sum is four

Subtraction 4 - 2 = 2 is "Four minus tw,o equals two" or

"Fout' minus tv,o is tv,0"

The result of this operation is called the tlifference Thus, if two issubtracted from four the difference is tn'o

Division.4 + 2 =2 rs "Four dividecl by tv'o equals tv'o" The result

of this operation is called the cluotienr Thus, if ten is divided by five, thequotient is two

Multiplication.4 x 2 = 8 is "Fow'multiplied by tv,ct equals eight"

or "Four times tv,o ecluals eight" The result of this operation is calledthe prcttlucl Thus, if four is multiplied by two the product is eight

Decimals In spoken English, 2.4 is "Trvo point four" The periodbetneen 2 and 4 is known as the decimal ooint

8.1 is "eight point one";

8.01 is "eight point zero one"/ "eight point nought one"

0.0013 is "zero point zero zero one three"

"nought point nought nought one three"

If 100 is divided by 3, and the quotienr is written 33.333, ir iscorrect to three significant figures If the quotient is written 33.33 it iscorect to two significant figures

LABORATORY GLASSWARE

Reaction vessels and containers

Beakers

A beaker is a simple container for liquids, very commonly used

in laboratories Beakers are generally cylindrical in shape, with a flatbottom Beakers are available in a wide range of sizes, from lml, up to

2 6

several litres.They may be made of glass

(very often Pyrex) or of plastic Beakers

used for holding solutions of corrosive

chemicals, such as acids, should be made

of Teflon or other materials resistant to

corrosion, eg borosilicate glass

Flasks

o Erlenmever flasks

An Erlenmeyer flask, also known as

conical flasks, is a widely used type of

laboratory flask which features a conical

base with a cylindrical neck They are

usually marked on the side (graduated) lo

indicate the approximate volume of their

contents.The flask is used to heat or boil

substances over a Bunsen burner flame or

hot plate

o Volumetric flasks

A volumetric flask is a type of

laboratory flask used to contain or measure a

very precise and accurate amount of a liquid

It is shaped like a Florence flask with

a flatter bottom so as to not tip over The

single, rather long, narrow neck is marked

(usually by a circumferential scratch or

etch on the glass) at a very Precise

2 ,

Beaker

Roun4-bottom flasks

Flasks come in a number of shapes and a rvide range of sizes, but acornmon distinguishing aspect in their shapes is a rvider vessel "body"and one (or sometimes more) narrower tubular sections at the top callednecks which have an opening at the top

Two or three-necked flasks are common as well Round bottom flaskscome in many sizes, from 5 mL to 5 L, rvith the sizes usually inscribed onthe glass The ends of the necks are usually conical (female) ground glassjoints These are standardized and can accept any similarly-sized ta$reid(male) fittings Standard Taper 24140 is common for 250 mL or larger flasks,while smaller sizes such as 14 or 19 are used for smaller flasks

Flasks can be used for making solutions or for holding, containing,collecting, or sometimes volumetrically measuring chemicals, samples,solutions, etc for chemical reactions or other processes such as mixing,heating cooling, dissolving, precipitation boiling (as in distillation), oranalysis

One neck Flask

Three neck Flask

2 8

Two neck Flask Three neck Flask

amorphous, rlrlj (thuoc ve) \,o dinh hrnh

attach, r' -to gan vdo

aqueous/ nonaqueous, adj (thuoc vd) nu6c/ khOng phii nudc,!.: j bond, r' li€n kdt

bind/bound, v lien kei gAn ket vao nhau

broken down into phAn cdt thdnh, phAn ra thhnh

building block khoi ket cAu, don vi cau tao

combine, r, - with ket hqp

combination, n

\ composition, n thdnh phdn

variable composition - thay d6i

uniform composition - d6ng nhat

\- compound, n hqp chat

compressible, adj c6 thO n6n duoc

_ constanr, adj khong ddi, hang sO

su kh6c nhau, hiOu soph6p chia

ti trong/ dhy dac, nangri€ng biOt, ri€ng rEroi loan, mat trat tunguy0n to

ong dong (chia dd)(thu6c ve) dOng thd(thuOc r'6) di thdnhAn dang nhAn biet

su nhAn d4ng, su giong nhau

so luong vo hantr6n lAn, hoh vho nhau(thuoc vd) Ion

khoi luongvAt chat, chatkim loaihqp thdnh til, tao thhnh tt

phuong ph6p(thuoc Vi) phan tu(thuoc vd) phAn tii l6n, dai PhAntu

dau trilphAn tuphdp nhAnhat tidu phAndau c6ng

thuong so

phAn tiich, tdchdung dichcau trfcchattidu hqp phdn, dudi hqp phdnph6p trtt

dac thir dac hieutu/ thuAt ngf

t l I

1 Chemists and physicists have used the observed properties of matter

to deyelop models of the individual units of matter- These modelscoilectir,ely make up what we now know as the atomic theory of matter'

These models have developed from experimental observations

i or.I- rhe past 200 years Thus theory and experirnent reinforc-e eaih other'

We rnusr gain some ins-ight into atomic structure to appreciate thebehavior of the atoms themselves as well as larger aggregates I of atom:compounds

The basrc structural unit of an element is the atom, which is the

p smallest unit of an element that retains the chemical properties of that

32

element The_atom is composed of three primary particles: the electron.the proton, and the neutron.,

,The atom has trvo distinct regions The rutcleus is a small, dense,positively charged region in the center of the atom composed of,l(positively charged protons and uncha rgTd neutrons Surrounding thenucleus is a diffuse region of negative charge occupied by electrons, the,o\r of the negative charge Electrons are tiny in comparison to protonsand neutrons

The atomic number (Z) is equal to the number of protons in the'_c

atom The nass number (A) is equal to the sum of the protons andneutrons (the mass of the electrons is insignificant)

Isotopes are atoms of the same element that have different massesbecause they have different numbers of neutrons (different massnumbers) Isotopes have behavior identical to that of any other isotope of

- the same element

Ions are electrically charged particles that result from a gain or loss ofone or more electrons by the parent atom Aniozis, negative ions, are formed

by a gain of one or more electrons by the parent aIom Catio,ns positive ions,tlare formed by a loss of one or more electrons from the parent atom

DEVELOPMENT OF THE ATOMIC THEORY

rt

_-ihL first experimentallv basef, theory of atomic structure was

@oposed _9y- Jotrn Dalton, wtro pittilreiO ailms as indivisible Thed*-peiin6ltrt of W C5lef.t,,p Goldstein, and J.J, thomson indicated thatthe'atom is composed of charged particles: protons and electrons The(third fundamental atomic paficlq

, 1:., th" neurron An experimenrconducted'by Fl.Geiger led El Ruthe'iford to propose thar the majority ofthe mass and positive charge of the atom was located in a small, denseregion, the nucleus, with small, negatively charged electrons occupying amuch larger, diffuse space outside of the nucleus

t"d Niels Bohr proposed an atomic model that described the atom as rngcleus surrounded by fixed €nergv- levels (or cluantum levels) that can beoccupied by electrons He believed that each level was defined br acircular orbit located at a specific distance from the nucleus

e ' l

P r o m o t i o n a n d r e l a x a t i o n p r o c e s s e s a r e r e f e r r e d | o f S e l e c t r o | l l c

( turtsitiDrts Electron promotion resulting-iionr-auserptron of energy

results tn an ercitecl stctte atom: the process of relaxation allows the atom

to retum to the gt.ottncl state.T]te modern \,iew of the atom describes the

probability of finding an electron in a region.ol'potE within the principal

cners.Y level rpterred ' , : , l ' l to as an atomic ut'bitul' The rapid movement of the

t - 0 e l e c t r o n S p t e a d s t h e m i n t o a c l o u d o f c h a r g e T h i s c l o u d i s m o r e d e n s e i n

c e r t a i n r e g i o n s ' t h e d e n s i t y b e i n g p r o p o r l i o n a l t o t h e p r o b a b i l i t y o f

f i n d i n g t h e e l e c t r o n a t a n y p o i n t i n t i m e T h e a r r a n g e m e n t o f e l e c t r o n s i natomic orbitals is the e/ectrott configuratiort'

Notes:

- To develoP models

- Gain some insight into

- Retains the chemical ProPerties

- In comParison to

- Have behavior identical to

- The Parent atom

- The exPerimentallY based theorY

- Be referred to as

A C O M P R E H E N S I O N Q U E S T I O N S

Ansv'er the follov'rng questtons:

t How was the atomic theory of matter developed?

t Hou is an atom defined?

3 Hou is the nucleus defined?

4 what is the difference between isotopes of the same element?

5 How are ions formed from atoms?

B T R U E - F A L S E S T A T E M E N T S

Write "True" (T) or "False" (F) beside each statement according

to the information fi'om the text.

1 i An element has the chemical behavior identical to that of

6 L The excited state of an atom has much more energy than

its ground state

7 l The electron configuration is described as the probability

of finding the electron at any point in time

C S E N T E N C E C O M P L E T I O N

Based on the information fi'om the text, complete the followirt<sentences

1 Almost all atoms consist ,.,.

2 Nucleus composed of 1

3 The size of the electron is

-1 Electron confisuration is defined as

E.romple: Substances are divided into elements and compounds

Form:

Simple Present: am / is / are

Simple Past : was / rvere

Present Continuous : am lis / are being j !'erb (Past Participle)Past Continuous : was/ were being

Present Perfect : have / has been

Past Perfect : had been

The Past Participle of regular verbs ends in -ED There are manycomn-ton irregular verbs

,Voles.'

Some verbs (give, get ) has two objectives, a person and a thing

In the Passive u'e often make the person the subject, not the thing

E.runtple'

He nas -eiven a new thermometer for measuring temperature ofreaction

3 6

Exercise 1

Change tlte follov,ing active sentences to passit,e

l Scientists divide elements into metals and non-metals

2 We carried out the reaction in the presence of a catalyst

3 I entered the laboratorv when my student was separating the products

by-4 A scientist is developing a neu' solvent norv

5 Lavoisier gave the name of hydrogen to this element

6 He was heating the solution for 2 hours

;

7 In 1896 scientists found that compounds of uranium emitted raysthat affected a photographic plate

8 We can dissolve fats in benzene

9 An American Julian Hill invented nylon in earlv 1930s

10 They use nylon to make parachutes and tyres

Passiye voice:Air is believed to consist o/several gases

It is believed that air consists of several gases

l People know that all kinds of matter consist of little particlescalled molecules

- Shape : cuuic, spherical, rectangular

: Material: rvooden, iron, metal, golden

- Function : it is used for verb-ing

- Size : indicated by the dimensions

I t i s i n le n g t l t - It is long

heigltt - high

u,idth - v'ide

depth - deep

- Mass : e.g the weight in kilograms

The shapes of objects may be:

Hollow \r, ,, , tube cylindrical

To describe the three-dimensional size of an object we use thefollowing nouns and adjectives /

There are several ways to describe the size of an object

What is the

{ height{ width of' ?{ length

{ height

x Its { width is { length{ height

* It is in { width

{ length{ height

* It has a { width of

{ length{ height

I of the copper block is 5 centimeters r

l The copper block is 5 centimeters lt ' I : I

3 The copper block ir lt, .'' .'.' bf 5 centimeters

-1 The copper block is 5 centimeters

Similarlr' describe the width and the length of this copper block

We can also describe the size of an object by using:

DiameterCircumference

For example,

1 The volume of the copper bar is 1600 cubic centimeters

2.The copper is 1600 cubic centimeters in volume

3 The copper bar has a volume of 1600 cubic centimeters

Exercise 2

Choice the right v'ays to describe ott orea

, 1 ' , 1

l The plate area of six square metres

2 The plate is six square metres r.'.larea

3 .' area of the plate is six square metres

All kinds of (l) are now knorvn to consist of little particles

called (2): these molecules in tum are discovered to consist of still

smaller particles called (3) The name "atom" comes from the Greek

word meaning (4) An atom contains (except for hydrogen) three

(5) of particles, which (6) only a portion of the whole space of the

ulo4; They are electrons, protons, and neutrons The posilively (1) l^tr(lrr1+ptfi of hydrogen is a proton The mass of the proton is found to be 1836

times greater than that of the electron The electrical (8) of the proton

is equal in magnitude to the charge of the electron, but it has the opposite

sign (+) instead of (-) The electrons are the outer (9) of the atom The

neutron has no charge at all and its mass is assumed to be approximatelv

equal to that of the proton The electrons and the nucleus are very small as

compared with the (10) of the atom, which, therefore, appears to be

composed largely of empty space

t I

C M A T C H I N GExercise 1Mutching the synonyms in the colunms A anctB.

?_ t":ef"d_

1 0 d e p e n d e n t

Exercise 2Make up true senten(.es ft-ont the tuble belov,

2 Sulphur ciirlrs.r steel to be brittle when hot, and phosphorus carr.er

it to be brittle u'hen cold

but it is also veryimportant for life

It is desirable rhal varies slightly in is called a solventThe liquid are aboul should be pure )

3 It was discovered that the rays from radium and other radioactiveelements may catse regression of cancerous growths.

4 Radioactive rays were observed to caltse the air through which theypass to become a conductor of ele-ctricity

5 If particles of varying size in a suspension need to be separated, thetube can be spun in the centrifuge for a period of time at a speedsufficient ro cause the heavier particles to move to the bottom of thetube before the lighter particles

6 A loss of an alpha particle causes a transformation of the atom aswell as a loss in mass

7 The change in magnetic force couses a florv of cunent that can bemeasured by a galvanometer

8 The increase in the concentration of one of the reactants calrses thereaction to go in the forward direction r

9 However, in the case of molecules which readily exchange pathswith each other attempts aI separation may cLutse molecularrealTangements

10 The next question to be considered is the nature of the radiationthat nuclear decay causes

B.Translate the follov,ing sentences into Englislt

l Ciic nguyOn t& la cr4c kh6i ket ciu khong thd phan chia crja tat ca vAt chat

.-2 PhAn tri gdm hai hoac hon hai nguy€n tri li€n ket vdi nhau

3 MOt s6 phin tir chi chfa c6c nguy€n tri ctra cing m6t nguyOn 16

4 C6c phAn tri khric chfa ciic nguy€n tu cua hai hoac hcn hai nguyen to

5 C6c electron vh hat nhAn rat nh6 so v6i kich thudc cia nguyOn tu

6 Thdnh phdn hori hoc cria nudc tinh khiet lu6n giong nhau

l Trong lugng nguy6n tir cira m6t nguyOn to n6i cho chring ta biet solugng proton ve ndtron trong hat nhAn cua nguyen tu

8 Ciic nguy€n tu khong the bi phai huy hay thay dCii trong suot phanring ho6 hoc

+ 1

9 Mo hinh cua Bo ld su d6ng g6p rat quan trong cho vi€c hieu bietciru trdc nguyen tu.

10 Tiing di€n tfch cua c6c electron bang di€n tich cua hat nhAn

In the case of the three hydrogen isotopes, the less isotopes withone proton and one neutron in the nucleus is called deuterium, and theisotope with one proton and two neutrons is called tritium This practice

of giving individual names to the different isotopes of an element is notdone with element other than hydrogen The exception in the case ofhvdrogen is due to the relatively large differences in properties caused byadditional neutrons in the nucleus

The different isotopes of an element are usually specified by means

of mass numbers rather than by names The mass number of an isotope isthe total number of protons plus neutrons present in the nucleus of theatom Thus for the lightest hydrogen atom, the mass number is 1; fordeuterium the mass number is 2: and for tritium the mass number is 3.The symbolism used is',H, t,H, t,H; here the subscript is the atomicnumber and the superscript is the mass number The atomic number is thenumber of protons present in the nucleus of the atom

44