Exothermic Reactions

Q. Quicklime $\left(\text{CaO}\right)$ reacts with water to form slaked lime ${\text{Ca(OH)}}_2$. During this process:

1. Heat is released
2. Heat is absorbed and then released
3. Heat is neither absorbed nor released
4. Heat is absorbed

Q.

Is melting endothermic or exothermic?

Q.

Respiration is an endothermic reaction.

1. True

2. False

Q. Burning of wax is a change and an process.

1. physical
2. chemical
3. exothermic
4. endothermic

Q.

Name:

The acid used in the preparation of a non-volatile acid.

Q.

How Long Does Electrolysis Rust Removal Take?

Q.

Which of the following is not a characteristics of a chemical change?

1. It is a permanent change

2. Exchange of energy take place

3. No new substance is formed

4. The change is irreversible

Q.

Write a word equation for a reaction in which sodium carbonate reacts with hydrochloric acid.

Q. Which among the following is/are an exothermic reaction?

1. Respiration
2. Burning of coal
3. Photosynthesis
4. Decomposition of calcium carbonate

Q.

Which of the following reactions are exothermic in nature?

(i) Evaporation of water
(ii) Dissolution of sodium hydroxide in water
(iii) Dilution of sulphuric acid
(iv) Dissolution of ammonium chloride in water
(v) Combustion of methane gas

1. (i), (iv) and (v) only

2. (ii), (iii) and (v) only

3. (i), (ii) and (iv) only

4. (i), (iii) and (iv) only

Q.

Distinguish between endothermic and exothermic reaction.

Q.

When hydrochloric acid is added to magnesium, which gas is liberated?

1. Nitrogen

2. Chlorine

3. Hydrogen

4. Oxygen

Q.

Give chemical equations for the following:

Combustion of ammonia

Q.

What happens when water is added to quick lime (calcium oxide)?

Q.

State the types of change involve when there is a change of energy by giving a proper example.

Q.

Give an example of an exothermic reaction.

Q.

A dilute solution of sodium carbonate was added to two test tubes - one containing dilute $HCl$ (A) and the other containing dilute $NaOH$ (B). The correct observation was

1. A brown coloured gas liberated in test tube B.

2. A brown coloured gas liberated in test tube A.

3. A colourless gas liberated in test tube B.

4. A colourless gas liberated in test tube A.

Q.

The process of passing an electric current through a liquid is known as ___________.

1. filtration

2. electrolysis

3. painting

4. galvanization

Q.

Define combustion reaction.

Q.

Which of the following are exothermic processes?

1. The reaction of quick lime with water
2. Dilution of sulphuric acid
3. Evaporation of water
4. Sublimation of camphor

1. (i) and (ii)

2. (ii) and (iii)

3. (i) and (iv)

4. (iii) and (iv)

Q.

Balance the following chemical reaction by identifying the products:

${\mathrm{Al}}_2{\mathrm{O}}_3+{\mathrm{N}}_2+\mathrm{C}\to \mathrm{AlN}+\mathrm{\_\_\_\_\_}$

Q. Zn+Hcl---------->ZnCl2+H2. what is the nature of chemical reaction ?

Q. What is. an exothermic reaction

Q.

Which among the following is an exothermic reaction?

1. Melting solid salts

2. Photosynthesis

3. Decomposition of mercuric oxide

4. Respiration

Q.

The reaction in which heat and light are liberated is called endothermic reaction.

1. Exothermic reaction

2. Endothermic reaction

Q. The table below shows some fuels along with their calorific values and ignition temperatures.
$$\begin{array}{ccc}\text{Fuel}& \text{Calorific value (kJ/kg)}& \text{Ignition Temperature (}{}^{\text{o}}\text{C)}\\ \text{A}& \text{100}& \text{5}\\ \text{B}& \text{80}& \text{50}\\ \text{C}& \text{30}& \text{60}\\ \text{D}& \text{20}& \text{70}\end{array}$$
Which of these can be considered as an ideal fuel?

1. B
2. D
3. C
4. A

Q.

Complete and balance the following chemical equation:

$\mathrm{\_}+6.5{\mathrm{O}}_2\to 4{\mathrm{CO}}_2+5{\mathrm{H}}_2\mathrm{O}+\mathrm{Heat}$

Q. When a candle burns, is it possible to get the wax back
(a) after the wax melts?
(b) after the wax burns?
(HINT: Are these phyusical changes or chemical changes?)

Q.

When magnesium ribbon reacts with air, heat and light is produced. The balanced chemical equation is:

$2\text{Mg}+{\text{O}}_2\to 2\text{MgO}$

The reactant(s) in the reaction is/are:

1. Mg

2. $O_2$

3. MgO

4. $M{g}_{2}O$

Q.

Which among the following is/are an exothermic reaction?

1. Respiration

2. Burning of coal

3. Photosynthesis

4. Decomposition of calcium carbonate into carbon dioxide and calcium oxide.