ICSE ICSE Class 7 - CISCE Question Bank Solutions

Give a word equation for the following reaction.

A salt which reacts with ammonium hydroxide to give a reddish brown precipitate.

Give a word equation for the following reaction.

An exothermic reaction where both the reactants are gases, one of which is oxygen.

Give reason for the following:

Even though rusting is an exothermic reaction, the heat evolved when an iron nail rusts is unnoticeable.

Give reason for the following:

Electrolytic decomposition of water is a reaction involving change of state.

Give reason for the following:

A characteristic change of colour is seen when a piece of iron is added to copper [II] sulphate solution.

Give reason for the following:

The catalytic oxidation of sulphur dioxide to sulphur trioxide is represented by a double arrow {⇌} 
between the reactants and products, formed in the chemical reaction.

Explain in brief the involvement of energy in physical and chemical changes.

Fill in the blanks with the appropriate words of the statement  given below:

Chemical changes may involve exchange of energy in the form of __________ and _________.

Fill in the blank with the correct word of the statement given below:

Ammonium chloride, a sublimable solid undergoes _________ on heating.

Name the following:

The products obtained during ‘photosynthesis’ – which is a chemical change.

Name the following:

The type of change physical or chemical involved – ‘during respiration in human beings’.

State the meaning of the term Air

State the meaning of the term atmosphere.

Name the important scientists and their studies which led to the discovery of the components of air.

Explain Lavoisier’s experiment which provided evidence to the discovery of components in air.

Explain the term ‘air pollution’, with reference to air quality. State the sources of a few main pollutants.

Match the statements in List I with the correct answer from List II.

Fill in the blank:

Nitrogen of the air is utilized by plants for formation of _____.

Fill in the blank:

The gas evolved as a product of combustion as well as respiration is ______.

Fill in the blank:

A candle burns in a jar of oxygen, but gets extinguished in ______