1 Normal Acad Chem

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Section A – Multiple Choice Questions (10 marks) 11. An unknown substance, P, cannot be broken down into simpler substances by any chemical methods. What could P be? A. B. C. D.

an alloy a mixture an element a compound

12. Which of the following statements about elements in the Periodic Table is not true? A. B. C. D.

Magnesium is a transition metal. The horizontal rows of elements are known as Periods. The vertical columns of elements are known as Groups. Elements are classified into Groups according to their chemical properties.

13. When dry ice (solid carbon dioxide) was heated, carbon dioxide gas was immediately produced. Which of the following processes had occurred? A. B. C. D.

boiling melting evaporation sublimation

14. Which of the following changes is not a chemical change? A. B. C. D.

melting burning electrolysis precipitation

15. Which element has the symbol ‘Na’? A. B. C. D.

neon sodium calcium nitrogen

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16. Which of the following is not an example of a decomposition reaction? A. B. C. D.

boiling of water rotting of bread heating of sugar electrolysis of water

17. Which of the following statements is true? A. B. C. D.

Mixtures are formed when there is a chemical reaction. Mixtures cannot be separated into their respective components. Compounds and mixtures differ because mixtures can only be liquids. Compounds are formed by the chemical combination of elements.

18. Which of these elements can conduct electricity? A. B. C. D.

argon oxygen nitrogen magnesium

19. Which of the following is true about dissolving salt in water? A. B. C. D.

A new substance is formed. A reversible change has occurred. Salt has changed from solid state to liquid state. There is an exchange of energy between the surrounding and the mixture.

20. Which of the following is an element that is required for iron to rust? A. B. C. D.

fluorine water oxygen potassium

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Section B -Short Structured Questions (20 marks) 1.

salt

nitrogen silver

air

orange juice

steel

Classify the above materials into elements (metals or non-metals), compounds and mixtures in the table below. Elements Compounds Mixtures Metals Non-metals

[3] 2.

evaporation

expansion

condensation

decomposition

Choose one word from the box above that is best used to describe the following changes (a) – (d). (a)

Changes water vapour changing to water droplets

______________________

(b)

mercury rising up the thread of a thermometer

______________________

(c)

decaying leaves

______________________

(d)

pools of water drying up under the hot sun

______________________ [4]

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3. Chlorine is an element. (a) Which Group does chlorine belong to? _________________________________________________________________ (b) Name an element that is in the same Group as chlorine. _____________________ (c) Chlorine is a poisonous gas. Using this information, predict one property of the element you have named in part (b). __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ [3]

4. Name one object which can be found in the kitchen that is made from the following elements. (a) Silver: ____________________________________________________________ (b) Tin :

____________________________________________________________ [2]

5. When an electric current is passed through water, water breaks down to give oxygen and hydrogen. (a) What is the name for this kind of chemical reaction? __________________________________________________________________ (b) Write a word equation for the above reaction. __________________________________________________________________ [2]

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6. Give three differences between compounds and mixtures. Compounds (a)

Mixtures

(b)

(c)

[3] 7. (a) What is oxidation? Explain by giving an example. __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ [2] 7

(b)

Explain why oxidation is considered to be a chemical reaction. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ [1]

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Section C- Free Response Questions (10 marks) The pie chart below shows the composition by mass of elements that make up the earth’s crust.

(a) Write down the names of the two main elements that make up the earth’s crust. _______________________________________________________________ [2] (b) Write down the symbol of nickel.____________________________________ [1] (c) State whether each of the elements below is a metal or a non-metal. (i) iron: ___________________________________ (ii) oxygen: ________________________________ (iii)

aluminium: _____________________________

(iv)calcium: _______________________________

[4]

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(d) State three differences between the properties of oxygen and the properties of iron.

____________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ ____

____________________________________________________________________ ____________________________________________________________________ __

____________________________________________________________________ _

____________________________________________________________________ _

____________________________________________________________________ _

____________________________________________________________________ _

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____________________________________________________________________ _ [3]

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