Chemistry Physical & Chemical Change Exercise 2b
Please Select
1 Complete the following statements.
(a) The chemical change involving iron and hydrochloric acid illustrates a ____________ reaction.
(b) In the type of reaction called__________two compounds exchange their positive and negative radicals.
(c) A catalyst either ______ or _________ the rate of a chemical change but itself remains__________at the end of the reaction.
(d) On heating, hydrated copper sulphate changes its colour from______ to___________
Solution :
2 When hydrogen burns in oxygen, water is formed; when electricity is passed through water, hydrogen and oxygen are given out. Name the type of chemical changes involved in the two cases.
Solution :
3 Explain, giving one example for each of the following chemical changes:
(a) Double decomposition
(b) Thermal dissociation
(c) Reversible reaction
(d) Displacement
Solution :
4 (a) What is synthesis?
(b) What kind of chemical reaction is synthesis? Support your answer by an example.
Solution :
5 Decomposition brought about by heat is known as thermal decomposition. What is the difference between thermal dissociation and thermal decomposition?
Solution :
6 (a) Define neutralization reaction with an example.
(b) Give a balanced equation for this reaction.
(c) Give three applications of neutralization reactions.
Solution :
7 What do you understand by a precipitation reaction? Explain with an example.
Solution :
8 (a) What are double displacement reactions?
(b) Give an example of a double displacement reaction, where gas is evolved.
Solution :
9 (a) What is a decomposition reaction ?
(b) Decomposition reactions can occur by (i) heat (ii) electricity and (iii) sunlight.
Give two balanced reactions for each.
Solution :
10 State the type of reactions each of the following represent and balance the ones that are not balanced.
(a) Cl2 + 2KBr → 2KC1 + Br2
(b) NaOH + HCI NaCl + H2O
(c) 2Hg0 -> 2Hg + 02
(d) Fe + CuSO4 FeSO4 + Cu
(e) PbO2 +SO2 PbSO4
(f) 2KClO3→ 2KCl + 3O2
(g) 2H2O2→ 2H2O + O2
(h) KNO3 + H2SO4 → HNO3 + KHSO4
(i) CuO+H2→ Cu+ H2O
(j) CaCO3→ CaO+ CO2
(k) NH4Cl → NH3 + HCl
(l) PbO + 2HNO3→ Pb(NO3) + 2H2O
(m) AgNO3 + NaCl → AgCl + NaNO3
Solution :
11 Match the following:
a. Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g) i) Photochemical decomposition b. 2AgCl(s) sunlight → 2Ag(s) +Cl2(g) ii) Thermal decomposition c. 2KCl electricity → 2K +Cl2 iii) Displacement reaction d. 2Hg)(s) Δ → 2HgS+O2 iv) Electrolytic decomposition
| a. Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g) | i) Photochemical decomposition |
| b. 2AgCl(s) sunlight → 2Ag(s) +Cl2(g) | ii) Thermal decomposition |
| c. 2KCl electricity → 2K +Cl2 | iii) Displacement reaction |
| d. 2Hg)(s) Δ → 2HgS+O2 | iv) Electrolytic decomposition |
Solution :
12 Multiple choice:
a. Which of the following is not a characteristic of a chemical change?
i. It is irreversible.
ii. No net energy change is involved.
iii. New substance is formed.
iv. Involves absorption or liberation of energy.
b. A reaction of a type: AB + CD → AD + CD, involves
i. No chemical change
ii. Decomposition of AB and CD
iii. Exchange of ions of AB and CD
iv. Combination of AB and CD
c. The reaction BaCl2(aq) + H2SO4(aq) → BaSO4(s) + 2HCl(aq) is
i. Displacement reaction
ii. Neutralisation reaction
iii. Decomposition reaction
iv. Double displacement reaction
d. Thermal decomposition of sodium carbonate will produce
i. Carbon dioxide
ii. Oxygen
iii. Sodium hydroxide
iv. No other product
Solution :
Contact Us
