Exothermic Reaction

Q.

Under what conditions heat can be given to a substance without raising its temperature?

Q.

When a mixture of iron powder and sulphur powder is heated strongly to form iron sulphide, then heat energy is :

(a) released (b) first absorbed and then released

(c) absorbed (d) neither absorbed nor released

Q.

Which of the following process / processes release heat ?
(i) condensation (ii) vaporisation (iii) freezing (iv) melting

(a) only (i) (b) only (iv) (c) (i) and (iii) (d) (ii) and (iv)

Q.

Give reasons for the following

1. Heating hydrated copper sulphate crystal is deemed a chemical change.

2. Efflorescence is minimum during humid conditions.

Q.

Combustion is-

1. physical and chemical change

2. physical change

3. chemical change

4. not a change

Q. Which type of change occurs when iron is heated with sulphur Powder

Q.

The reaction of Quicklime turning into Slaked Lime is ___ which turns___ .

1. Exothermic, Blue Litmus Red

2. Endothermic, Blue litmus Red

3. Endothermic, Red litmus Blue

4. Exothermic, Red Litmus Blue

Q.

What do you observe when burning magnesium is lowered in a jar of CO₂ ?

Q.

During combustion only dust is released.

1. True
2. False

Q.

Find the odd one out

1. Effervescence

2. Precipitate

3. Color change

4. Oxidation

Q.

Which among the following is an exothermic reaction?

1. All of the given options

2. Reaction during respiration

3. Melting solid salts

4. Photosynthesis

Q.

Burning of fuel is a/an ___ reaction.

Q.

Which of the following is not a combustion reaction?

1. Boiling of water

2. Melting of wax

3. Burning of petrol.

4. Freezing of Ice

Q. A process in which heat is released along with the formation of products is called ___.

Q. Respiration is an exothermic reaction.

1. True

2. False

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

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

Q.

Write a non- exothermic reaction taking place in blast furnance during extraction of iron?

Q. Assertion: Nitrogen and hydrogen combine together to form ammonia.
Reason: It is an exothermic reaction.

1. Both assertion and reason are true and the reason is the correct explanation of assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of assertion.
3. The assertion is true but the reason is false.
4. Both assertion and reason are false.

Q.

The oxidation reactions which produce light and heat are known as _______________.

1. exothermic reaction

2. combustion reaction

3. photochemical reaction

4. endothermic reaction

Q.

Respiration is an endothermic reaction.

1. True

2. False

Q.

Design an experiment to show that air contains water vapour. [3 MARKS]