Worksheet on Elements, Compounds, Mixtures

8/6/2019 Worksheet on Elements, Compounds, Mixtures

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Worksheet on Elements, Compounds and Mixtures

Name : ___________________________ ( ) Date: 05042007

Class : _______________

Instruction: Answer all questions 1-9 below by filling the correct answer in the given bracket.

1. How many atoms are present in one molecule of sulphurous acid, H2SO3?

A 3B 5C 6D 8 ( )

2. A mixture ________.

A has a fixed melting point.B has a fixed boiling point.C is made by a chemical reaction.

D can be separated by physical methods. ( )

3. Which pair of substances are both mixtures?

A air; sea water B diamond; vinegar C ethanol; lime water D water; air

( )

4. Which picture shows a compound made of two elements.

( )5. Which element conducts electricity at r.t.p.?

A Bromine. B Nitrogen. C Sulphur.D Sodium. ( )

6. Which one of the following sets contains only one metal? A sodium hydrogen calciumB iron oxygen sulphur

C copper carbon calciumD sulphur magnesium copper ( )

7. Which one of the following is an element?A Salt

B Water C Air D Chlorine ( )



8 The structural formula of glycerol is

Which statement about glycerol is not true?

A Its molecular formula is C3H8O3.

B It contains three elements.

C One molecule contains a total of 14 atoms.D Its molecular formula and empirical formula are different. ( )

9. Which diagrams correctly show the molecules in ammonia, nitrogen andhydrogen?

ammonia nitrogen hydrogen

A

B

C

D

( )



Instruction: Questions 10-17 are structured questions. Fill your answers in theblank spaces provided

10. Choose your answers from the following list of substances.

air calcium carbon dioxidechlorine gold hydrogenice nitrogen sea water sugar

(a) Name four elements.

(b) Name two substances that are mixtures.

(c) Name two substances that are single compounds.

(d) Name one solid compound that contains the element carbon.

11(a) The formula of one molecule of nitric acid is HNO3.

(i) Name the elements present in nitric acid.

(ii) What is the total number of atoms in one molecule of nitric acid?

12. Fructose is a sugar used in food. The structural formula of one form of fructose is given below.



(i) What are the elements present in fructose?

(ii) What is the molecular formula of fructose?

(iii) What is the empirical formula of fructose?

13. A list of substances is given below.

Air Water Ethanol Steel Chromium

Graphite Petrol Nylon Protein

Choose from the list one substance which

(i) is an element.

(ii) is a compound containing two elements only.

(iii) is a compound containing nitrogen.

(iv) is a mixture of compounds.

(v) is a mixture of elements.

14(a) Substances can be classified as elements, compounds or mixtures. Put eachof the following into one of these classes.

(i) Air.

(ii) Ammonia.

(iii) Ethanol.



(iv) Iodine.

(b) Mixtures of metals (e.g. brass) are commonly called :

15. The properties of some metal oxides are given in the table. All the oxides are

solid at room conditions.

name of oxide formula of oxide

colour effect of heating the oxide

copper(I) oxide Cu2O red remains red

lead(IV) oxide PbO2 brown oxygen produced;

solid turns yellow

mercury(II) oxide HgO red oxygen produced;silvery liquid produced

potassium peroxide K2O2 white remains white

Zinc oxide ZnO white solid turns yellow when hot andbecomes white again on cooling

(a) Which of these oxides do not undergo a chemical reaction when heated?

...............................................................................................................................[2]

(b) Suggest the identity of the silvery liquid formed from mercury(II) oxide.

..........................................................................................................................

16 (a) State three differences in the properties of elements that are metals and

elements that are non-metals. Write your answer in the table below.

Property Metals Non-metals

1

23

(b) Anhydrite is a white rock with the formula CaSO4.

Name the elements present in anhydrite and state whether each one is a

metal or a non-metal.



17. Fig. B shows some of the molecules in the air above an active volcano. For

example, a water molecule has the formula H2O and is shown by in thediagram. Write the formulas for the other molecules in the air above the

volcano.

.

Fig B

18. Use examples :a mixture of iron filings and sulphur, a compound iron(II)sulphide to illustrate the differences of properties between a mixture and asingle compound. [4]

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Worksheet on Elements, Compounds, Mixtures