Endothermic and Exothermic Changes

Q.

When potassium permanganate is heated it produces potassium manganate, manganese dioxide and oxygen gas. This is an example of ______ reaction.

1. electrolytic

2. endothermic

3. exothermic

4. electrochemical

Q. Define the following terms
(i) Condensation
(ii) Freezing
(iii) Subimation

Q. Read the following statements and choose the correct option:
Statement 1: Burning of magnesium ribbon is an exothermic reaction.
Statement 2: Decomposition of potassium nitrate is an endothermic reaction.

1. Statement 1 is correct and statement 2 is wrong.
2. Statement 1 is wrong and statement 2 is correct.
3. Both statements are correct.
4. Both statements are wrong.

Q. Evolution or absorption of heat is an indicator of a chemical change.

1. True
2. False

Q. Which among the following are given out during respiration?

1. Carbon dioxide
2. Water
3. Glucose
4. Hydrogen

Q. Which of the following changes is exothermic in nature?​

1. Freezing of water
2. Evaporation of water
3. Melting of wax
4. Melting of ice

Q. In which of the following processes, change in the state of matter involves gaining of heat?

1. Boiling
2. Freezing
3. Condensation
4. Melting

Q. Which of the following chemical process is exothermic in nature?

1. Melting
2. Photosynthesis
3. Evaporation
4. Respiration

Q. [TBQ.XII.(2)]
Observe the picture containing a kettle and note that it has salt water in it and answer the following questions.

(a) What is name of the process that is done to the kettle?
(b) What will happen to the content of the kettle?
(c) What kind of change is occurring on the cold surface of the metal plate?
(d) What can you say about the quality of water that is obtained in the beaker?

Q. Which of the following are exothermic processes?
I. Melting ice cubes
II. Respiration
III. Burning of a candle
IV. Evaporation of water

1. I only
2. I & II
3. I & III
4. II & III

Q. Heat energy is either absorbed or evolved during a chemical change.

1. False
2. True

Q. Analyze the reactions given below and fill the suitable answer.
$\mathrm{Reaction}I:\mathrm{Reactant}+\mathrm{Heat}\to \mathrm{Product}\mathrm{Reaction}\mathrm{II}:\mathrm{Reactant}\to \mathrm{Product}+\mathrm{Heat}$
Reaction I is and reaction II is .

1. endothermic
2. exothermic
3. photochemical
4. electrochemical

Q. The burning of magnesium ribbon is an example of a chemical change because:

1. a new substance is getting formed.
2. heat is released during this process.
3. change in composition occurs
4. a loud sound is produced.

Q. <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Match the processes with their names.

1. Boiling
2. Freezing
3. Melting
4. Condensation

Q. Respiration is an endothermic process.

1. False
2. True

Q. Choose the correct pairs.

1. Heat evolution
2. Heat absorption
3. Insoluble product
4. Exothermic
5. Endothermic
6. Precipitate

Q. Mixing baking soda with vinegar cools the solution as the reaction is _______.

1. exothermic
2. endothermic
3. reversible
4. temporary

Q. Conversion of water into steam is a/an _______ process.

1. photolytic
2. irreversible
3. endothermic
4. exothermic