Page 149 - ICSE Chemistry 8

Review Your Learning

A. Answer in one word/a few words.
1. The chemical reac on in which heat energy is evolved _____________________

2. The chemical reac on that takes place when the electricity is
passed through the reactants _____________________
3. A substance that alters the rate of a chemical reac on _____________________

4. A substance that acts as a catalyst in a biochemical reac on _____________________
5. An atom or a group of atoms which loses electrons during a
chemical reac on _____________________
B. State whether the given statements are true (T) or false (F).

1. A blue precipitate of silver chloride is formed when sodium chloride and silver nitrate solu ons are
mixed together.
2. When water is added to quicklime, heat energy is evolved.
3. Photosynthesis in green plants takes place in the presence of chlorophyll that acts as a catalyst.

4. Roas ng is a decomposi on process in which a metallic ore is heated in the absence or limited
supply of air.
5. Sodium hydroxide and potassium hydroxide are strong alkalis.

C. Defi ne the following terms.
1. Endothermic reac on 2. Posi ve catalyst 3. Proteases 4. Synthesis reac on
5. Photodecomposi on 6. Reduc on 7. Oxidising agent 8. Calcina on

D. Complete and balance the following chemical equa ons.
1. NaNO _______ + O 2. Fe + CuSO _______ + _______
3
2
4
3. NH OH + _______ Fe(OH)  + _______ 4. Pb(NO ) PbO + _______ + _______
3 2
2
4
5. Cl + KBr _______ + Br 6. Na CO + _______ _______ + NaNO 3
2
2
3
E. Answer the following ques ons.
1. Give examples of chemical reac ons that are characterised by change of colour.
2. Diff eren ate between endothermic reac ons and exothermic reac ons with the help of examples.
3. What are the condi ons required for chemical reac ons to take place?
4. How is a catalyst diff erent from an enzyme?

5. What is the importance of neutralisa on reac ons in our daily life?
6. Write a note on classifi ca on of oxides.

PROJECT
Create a PowerPoint presenta on on the topic ‘Redox Reac ons’. Find the related informa on and images
using the Internet. Add audio and visual eff ects to your presenta on. Format it as per your choice.

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