Production of Light and Heat

Q.

On combustion of one mole of a hydrocarbon gives two moles of carbon dioxide and two moles of water and a large quantity of heat is produced. The hydrocarbon is

1. Methane

2. Ethane

3. Ethene

4. Ethyne

Q.

In the below image arrow (A) represents the heat going out while arrow (B) represents the heat coming in. Identify these types of reactions from the given options.

1. Arrow A:- Exothermic

2. Arrow B:- Exothermic

3. Arrow A:- Endothermic

4. Arrow B:- Endothermic

Q.

What happens when ethene is burnt in excess of oxygen.

Q.

What do you mean by endothermic reaction?

Q. Define photochemical reactions with an example. [2 Mark]

Q.

What do you understand by the term Chemical change.

Q.

Which one produces more heat on combustion - one-mole methane or one-mole propane?

Q. Burning of paper is a chemical change.

1. True
2. False

Q. While burning a candle, the melting of wax is a change whereas the burning of wick is a change.

1. physical
2. chemical
3. periodic
4. natural

Q.

The reaction which produces heat are known as ___.

1. endothermic reactions

2. photochemical reactions

3. combustion reactions

4. exothermic reactions

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

1. False
2. True