Warming-up　What Are Substances Composed of？

Text A　Elements and Compounds

Elements are pure substances that cannot be decomposed into simpler substances by ordinary chemical changes.At present there are 109 known elements.Some common elements that are familiar to you are carbon，oxygen，aluminum，iron，copper，nitrogen，and gold.

About 85% of the elements can be found in nature，usually combined with other elements in minerals and vegetable matter or in substances like water and carbon dioxide.Copper，silver，go1d，and about 20 other elements can be found in highly pure forms.Sixteen elements are not found in nature； they have been produced in generally small amounts in nuclear explosions and nuclear research. They are man-made elements.

Pure substances composed of two or more elements are called compounds.Because they contain two or more elements，compounds，unlike elements，are capable of being decomposed into simpler substances by chemical changes.

The ultimate chemical decomposition of compounds produces the elements from which they are made.

The compound carbon monoxide（CO）is composed of carbon and oxygen in the ratio of one atom of carbon to one atom of oxygen.Hydrogen chloride（HCl）contains a ratio of one atom of hydrogen to one atom of chlorine.Compounds may contain more than one atom of the same element. Methane（“natural gas” CH4）is composed of carbon and hydrogen in a ratio of one carbon atom to four hydrogen atoms. ordinary table sugar（sucrose，C12H22O11）contains a ratio of 12 atoms of carbon to 22 atoms of hydrogen to 11 atoms of oxygen.These atoms are held together in the compound by chemical bonds.

There are over three million known compounds，with no end in sight as to the number that can and will be prepared in the future.Each compound is unique and has characteristic physical and chemical properties.Let us consider in some detail two compounds——water and mercuric oxide.Water is a colorless，odorless，tasteless liquid that can be changed to a solid，ice，at 0℃and to a gas，steam at 100℃.It is composed of two atoms of hydrogen and one atom of oxygen per molecule，which represents 11.2 percent hydrogen and 88.8 percent oxygen by mass.Water reacts chemically with sodium to produce hydrogen and sodium hydroxide，with lime to produce calcium hydroxide，and with sulfur trioxide to produce sulfuric acid.No other compound has all these exact physical and chemical properties， they are characteristics of water alone.

Mercuric oxide is a dense，orange-red powder composed of a ratio of one atom of mercury to one atom of oxygen.Its composition by mass is 92.6 percent mercury and 7.4 percent oxygen.When it is heated to temperatures greater than 360℃，a colorless gas，oxygen，and a silvery liquid metal，mercury，are produced.Here again are specific physical and chemical properties belonging to mercuric oxide and to no other substance.Thus，a compound may be identified and distinguished from all other compounds by its characteristic properties.

Words and expressions

element[]n.元素

decompose[]v.分解

familiar[]adj.熟悉的

oxygen[ɑ]n.氧气

aluminum[]n.铝

copper[ɑ]n.铜

nitrogen[]n.氮

combine[]v.结合

small amounts少量

nuclear explosion核爆炸

ultimate[]adj.最终的

monoxide[ɒ]n.一氧化物

ratio[]n.比率

atom[]n.原子

chloride[]n.氯化物

chlorine[]n.氯

sucrose[]n.蔗糖

chemical bond化学键

in sight看得见

unique[]adj.独特的

characteristic[] adj.典型的

property n.性质

in detail详细地

solid[ɑ]n.固体

steam[]n.蒸汽

represent[]v.代表

sodium[]n.钠

lime[]n.石灰

dense[]adj.密度大的

identify[]vt.鉴定

distinguish[ɡ]v .辨别

Comprehension

Choose the best answer according to the text.

1.Water is composed of two atoms of hydrogen and one atom of oxygen per molecule，which represents 11.2 percent hydrogen and 88.8 percent oxygen by（　　）.

A.mass

B.volume

C.mole

D.molecule

2.Compounds may contain more than one atom of the same element.The following selections all comply with this sentence except（　　）.

A.CH4

B.HCl

C.C12H22O11

D.CO2

3.Mercuric oxide is a dense，（　　）powder composed of a ratio of one atom of mercury to one atom of oxygen.

A.green

B.colorless

C.orange-red

D.black

4.Which statement is not true according to the text？（　　）

A.Compound can be decomposed into simpler substances by chemical changes.

B.Gold can be found in highly pure forms in nature because it is inert.

C.Water reacts chemically with lime to produce calcium hydroxide and hydrogen gas.

D.The formula of mercuric oxide is HgO.

Vocabulary building

Active words

substance

n.[物]物质；实质

combine

v.结合

matter

n.物质；事情

form

v.形成

n.形式

nature

n.自然；性质

produce

v.生产；产生

n.农产品，产品

bond

v.结合

n.连接，键

react

v.反应

property

n.性质；财产

Useful expressions

be composed of 由…组成

be decomposed into 分解成

A reacts with B to produce C and D A与B反应生成C和D

ratio of … to… 比例为……

percent by mass 质量百分比

in sight 在即，在望；看得见

Exercise

Fill in each blank with a given word or expression in their right form.

react　　　compose　　　bond　　　combine　　　property　　　solid

1.Tannin is a plant polyphenol.It could_________protein in solution to form sediment.

2.England，Scotland and Wales_________the island of Great Britain.

3.An acid can_________with a base to form a salt.

4.One_________of red phosphorous is flammable.

5.Matter exists in three states：_________，liquid and gas.

6.These amino acids can react with each other to form a different kind of chemical_________.

Extension

The Elements

Tom Lehrer is an American singer-songwriter，satirist，pianist，and mathematician.

The Elements is one of his most famous creations，which consists of little more than the elements of the periodic table.

Listen to the song The Elements，and try to write down the lyrics.

Work in groups

Discuss with your group members about rules of word-formation of following elements.

chlorine　　oxygen　　sodium　　aluminum

carbon　　sulfur　　fluorine　　nitrogen

gold　　helium　　hydrogen　　calcium

Exercise

Match the given words or phrases with the right symbol in the periodic table of the elements.

Atomic weight　　Metal　　Non-metal　　Man-made element

Atomic number　　Rare gases　　Element symbol　　Arrangement of extra nuclear electrons

Text B　Systematic Nomenclature of Binary Compounds

（1）Binary compounds in which the electro-positive element has a fixed oxidation state. The chemical name is composed of the name of the metal，which is written first，followed by the name of the nonmetal，which has been modified to an identifying stem to which is added the suffix-ide. For example，sodium chloride，NaCl is composed of one atom each of sodium and chlorine.The compound name is sodium chloride.

Elements：sodium（metal）+chlorine（nonmetal）

Name of compound：sodium chloride

Stems of some common nonmetals are shown in the following table 1.1.

（2）Binary compounds containing metals of variable oxidation numbers and nonmetals.Two systems are commonly used for compounds in this category.The official system，designated by the International Union of Pure and Applied Chemistry（IUPAC），is known as the Stock system.In the Stock System，when a compound contains a metal that can have more than one oxidation number，the oxidation number of the metal in the compound is designated by a Roman numeral in parentheses[e.g.(II)]written immediately after the name of the metal. The nonmetal is treated in the same manner as in the previous case.

Examples：

FeCl2　Iron（II）chloride　　　（Fe2+）

FeCl3　Iron（III）chloride　　　（Fe3+）

CuCl　Copper（I）chloride　　　（Cu+）

CuCl2　Copper（II）chloride　　（Cu2+）

In classical nomenclature，when the metallic ion has only two oxidation numbers，the name of the metal is modified with the suffixes-ous and-ic to distinguish between the two.The lower oxidation state is given the-ous ending and the higher one the-ic ending.

FeCl2　ferrous chloride　　　（Fe2+）

FeCl3　ferric chloride　　　　（Fe3+）

CuCl　Cuprous chloride　　　（Cu+）

CuCl2　Cupric chloride　　　　（Cu2+）

（3）Binary compounds contain two nonmetals. The most electropositive element is named first. Between two nonmetals，the element that occurs earlier in the following sequence is written and named first in the formula：B，Si，C，P，N，S，I，Br，Cl，O，F. To each element is attached a Latin or Greek prefix indicating the number of atoms of that element in the molecule. The second element still retains the modified binary ending. The prefix mono is generally omitted except when needed to distinguish between two or more compounds. Common prefixes and their numerical equivalences are the following.

mono=1　di=2　tri=3　tetra=4　penta=5

hexa=6　hepta=7　octa=8　nona=9　deca=10

Examples：

CO 　carbon monoxide

CO2　carbon dioxide

PCl3　phosphorus trichloride

PCl5　phosphorus pentachloride

（4）Exceptions using-ide endings. Three notable exceptions using the-ide ending are hydroxides（OH-），cyanides（CN-），and ammonium（N）compounds.

NH4I　　　Ammonium iodide

Ca（OH）2Calcium hydroxide

KCN　Potassium cyanide

（5）Acids derive from binary compounds. Certain binary hydrogen compounds，when dissolved in water，form solutions that have acid properties. Because of this property，these compounds are given acid names in addition to their regular-ide names. However，not all binary hydrogen compounds are acids. To express the formula of a binary acid，it is customary to write the symbol of hydrogen first，followed by the symbol of the second element（e. g. HCl，HBr，H2S）.

To name a binary acid，place the prefix hydro-in front of，and the letter-ic after the stem of the nonmetal. Then add the word “acid”.

Examples：HCl Hydrochloric acid

H2S Hydrosulfuric acid

Words and expressions

binary[]adj.二元的

modify[]v.修改

stem[]n.词干

symbol[]n.符号

variable[]adj.可变的

oxidation numbers氧化价态

category[]n.种类

designate[]v.指定

IUPAC国际理论和应用化学联合会

parentheses[]n.

parenthesis的复数形式 圆括号

manner[]n.方式

suffix[]n.后缀

formula[]n.分子式

attach[]v.附加

prefix[]n.前缀

retain[]v.保留

omit[]v.省略

equivalence[]n.相等

derive[]v.源于

dissolve[]v.溶解

solution[]n.溶液

customary[]adj.习惯的

Comprehension

Choose the best answer according to the text.

1.According to the text，which compound owns multiple？names？（　　）

A.CO2

B.HCl

C.NaCl

D.KCN

2.Which one belongs to binary compounds only containing two nonmetals？（　　）

A.CO2

B.Ca（OH）2

C.NaCl

D.KCN

3.Two systems are commonly used for binary compounds containing metals of variable oxidation numbers and nonmetals.They are（　　）.

A.official system and Stock system

B.official system and classical nomenclature system

C.official system and IUPAC

D.IUPAC and classical nomenclature system

4.Which statement is not true according to the text？（　　）

A.H2S dissolved in water will form solutions that have acid properties.

B.HCl is named as hydrochloric acid or hydrogen chloride.

C.CO is named as carbon oxide because the prefix mono is generally omitted.

D.Ferric chloride and iron（III）chloride are the same chemical.

Match the formulae with their equivalents

Write the systematic nomenclature of the following chemicals.

H2________________　KOH________________

Ca________________　HCl________________

CO________________　SO2________________

NaCl________________　PCl3________________

Fe3+________________　PCl5________________

Fe2+________________　Ca（OH）2________________

Vocabulary building

Active words

variable

adj.可变的

n.[数] 变量

formula

n.公式；分子式；配方

attach

v.附属，附加

retain

v.保持

omit

vt.省略；遗漏；未（做）

exception

n.例外

express

vt.表达

n.快车，快递

dissolve

vt.溶解；解散，解除，消散

Useful expressions

consist of　由…组成；由…构成；包括

be known as　被称为；被认为是

derive from　来源于；衍生于

in addition to　除了

Exercise

Fill in each blank with a given word or expression in their right form.

in addition to　　consist of　　variable　　be known as　　dissolve　　express

1.Solubility is the degree to which a substance dissolves in a solvent to make a solution（usually_________as grams of solute per liter of solvent）.

2.Warm the sugar slightly first to make it_________quicker.

3.He is of a_________mood； he never finishes what he starts.

4.Mercury is the metal which is liquid at room temperature and is better_________quicksilver.

5._________Sinopec，37 other companies have also been punished for water pollution.

6.The atmosphere_________more than 70% of nitrogen.

Work in groups

Discuss with your group members about nomenclature of following organic substances and find out the common suffixes and prefixes.

Write the nomenclature of the following chemicals.

CH4________________________________________________

CH3CH2CH2CH3________________________________________________

C2H5OH________________________________________________

C6H6________________________________________________

Text C　Properties of Aqueous Ammonia

Ammonia is an important raw material for chemical industry and has a wide use in various industries.Therefore，the properties of ammonia are of importance.

Section 1　Physical and Chemical Properties

Appearance and Characters：Colorless liquid.

Melting Point（℃）：-77.7

Relative Density（1 for water）：0.82/-79℃

Boiling Point（℃）：-33.5

Relative Vapor Density（1 for air）：0.6

Saturated Vapor Pressure（kPa）：506.42/4.7℃

Combustion heat（kJ/mol）：No data available.

Critical temperature（℃）：132.5

Critical pressure（MPa）：11.40

Logarithmic Value of Octanol/Water Distribution Coefficient：No data available.

Flash Point（℃）：No data available.

Ignition Point（℃）：651

Upper Limit of Explosion，%（V/V）：27.4

Lower Limit of Explosion，%（V/V）：15.7

Solubility：The product dissolves sodium compound，potassium compound，sulfur compound and phosphorus compound，inorganic chloride，bromide，sulfonated bodies，cyanide，nitrate，nitrite，organic amine compound，phenol，alcohol and aldehyde，etc.Main Applications：The product is mainly used to produce fertilizer，and can be used as fertilizer directly.In industry it is mainly used to produce dynamite，various chemical fibers and plastics. They can be used as refrigerant as well.It is widely used in wood paper pulp production，metallurgy，oil refining，rubber，leather manufacture and medicine，etc.

Section 2　Stability and Reactivity

Stability：Stable at ambient temperature.

Incompatibility：Halogen，acyl chloride，acid，chloroform and strong oxidants.

Contact Avoiding Conditions：No data available.

Danger of Polymerization：Impossible to occur.

Decomposition Products：Hydrogen and nitrogen.

Section 3　Toxicology Data

Toxicity：The product is slightly toxic.It has an irritant and corrosive effect on the upper respiratory tract.The product with high concentration may increase the excitability of central nervous system，causing spasms.Ammonia and aqua ammonia may cause eye corneal edema，even corneal perforation.Aqua ammonia water may cause skin ambustion as well.

Words and expressions

aqueous[]adj.水的

ammonia[]n.[无化]氨

vapor[]n.蒸气

saturate[]vt.使饱和

combustion[]n.燃烧

critical[]adj.临界的

logarithmic[]adj.对数的

distribution coefficient[物化]分配系数

ignition[]n.燃烧

explosion[]n.爆炸

solubility[]n.溶解度

potassium[]n.钾

phosphorus[]n.磷

cyanide[,]n.氰化物

amine[]n.[有化]胺

phenol[]n.苯酚

aldehyde[,]n.醛

fertilizer[ɜ]n.肥料

dynamite[]n.炸药

fiber[]n.纤维

refrigerant[]n.制冷剂

pulp[]n.纸浆

metallurgy[ɜ]n.冶金

stability[]n.稳定性

ambient[]adj.周围的

incompatibility[,]n.不相容

halogen[]n.卤素

acyl chloride酰基氯

toxicology[]n.毒物学

irritant n.[医]刺激物，[医]刺激剂

corrosive[]adj.腐蚀的

respiratory tract呼吸道

spasms n.肌痉挛

eye corneal edema眼角膜水肿

corneal perforation角膜穿孔

ambustion[]n.灼伤

Comprehension

Fill in the blanks with the given words.

The passage is concerned with the properties of aqueous ammonia，which have great bearing on the safe handling procedures for the chemical.Let’s consider some properties in detail.

Boiling point is an indicator of how readily the chemical becomes a_________（gas/liquid/solid）.The_________（lower/higher）the boiling point，the more readily it vaporizes.The boiling point of ammonia is -33.5℃，so it should be in_________（gas/liquid/solid）state at room temperature.

The lower explosive limit（LEL）is the lowest concentration of solvent in air that will ignite.The upper explosive limit（UEL）is the highest concentration of solvent in air that will ignite.As a rule of thumb，the greater the range between the LEL and UEL，the greater the fire hazard.For example：

Ether　LEL=1.9%.UEL=36%

Aqueous ammonia　　LEL=15.7%.UEL=27.4%

Based on these values only，ether presents a_________（greater/less）fire hazard than aqueous ammonia.However，to determine the fire hazard accurately，flash point and vapor pressure would also need to be considered.

A vapor which is heavier than air（vapor density greater than 1）will tend to collect in pools and spread near ground level.A vapor which is lighter than air will tend to rise.Aqueous ammonia belong to the_________（former/latter）.

Vocabulary building

Active words

available

adj.可得的；可用的

concentration

n.浓度；集中；专心

critical

adj.临界的；关键的；批评的

manufacture

n.制造

v.制造

various

adj.各种各样的

application

n.应用；申请

body

n.身体；主体

Useful expressions

has an effect on　对……有影响

as well 也

Exercise

Match the parameters with their equivalents.

1.melting point

A.临界压力

2.flash point

B.着火点

3.relative density

C.闪点

4.ignition point

D.相对密度

5.critical pressure

E.蒸气压

6.vapor pressure

F.熔点

Translate the specification sheet into Chinese.

Properties of HAP

[usage]：mainly used in resin industry，used as dispersant，such as EPS，SAN，PS.The anti-adhesive separating agent，also applied in ceramic，biological material，fluorescent material etc.

[scientific name]：HAP

[molecular formula]：Ca2（PO4）6（OH）2

[properties]：White amorphous powder

[relative density]：3.18

[boiling point]：1670℃

[characteristics]：even grain distribution，stable production，easy control.No change the process and equipment，this product can be applied in suspension polymerization. Quality product in low price.

[technical index]：

[package＆ storage]：10kg/20kg in woven bag lined with double layers polythene bag.Keep in cool airiness dry place and avoid sunlight，rain and breakage.

Extension

How to get the useful information of chemicals？

Lange’s Handbook of Chemistry

Lange’s Handbook of Chemistry is a chemical data handbook with complete and accurate data，especially convenient for chemical and related scientific workers.

The book was compiled by N.A.Lange（1st-10th edition），followed by J.A.Dean（11th-15th edition）.The latest 16th edition was edited by J.G.Speight.

The book（16th edition）is divided into eleven sections：

Section 1.Organic Compounds

Section 2.General Information，Conversion Tables，and Mathematics

Section 3.Inorganic Compounds

Section 4.Properties of Atoms，Radicals，and Bonds

Section 5.Physical Properties

Section 6.Thermodynamic Properties

Section 7.Spectroscopy

Section 8.Electrolytes，Electromotive Force，and Chemical Equilibrium

Section 9.Physicochemical Relationships

Section 10.Polymers，Rubbers，Fats，Oils，and Waxes

Section 11.Practical Laboratory Information

The following table is extracted from Lange’s Handbook of Chemistry.According to the data in Table 1.2，answer questions：

1.How many drying agents are listed and what are they？

2.Which drying agents can be used for drying methane？

3.As a drying agent，K2CO3 is useful for most materials except acids，why？

4.which drying agent can be used only once？