ICSE ICSE Class 7 - CISCE Question Bank Solutions for Chemistry

Elements X and Y have 1 and 7 electrons in their outermost shell respectively.

Which will form negative ion?

Elements X and Y have 1 and 7 electrons in their outermost shell respectively.

What will be the charge present of the molecule XY after chemical combination?

Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.

Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.

Explain the meaning of the term matter with special reference to the term ‘substance’.

Explain the meaning of the term matter with special reference to the term ‘substance’.

Give examples of exothermic reactions i.e. heat evolved in each of the following:

(a) reaction between a solid and a liquid
(b) reaction between two gases
Give two examples of exothermic reactions seen in everyday life.

Select the correct answer for the following options:

The black residue obtained on heating copper carbonate.

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The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.

Select the correct answer for the following options:

The gas obtained when potassium chlorate is heated in the presence of a catalyst.

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The gas which reacts with oxygen to give a neutral liquid.

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The pale blue precipitated obtained when copper [II] sulphate reacts with sodium hydroxide.

Give a word equation for the following reaction.

Two solids which combine on heating, to give a liquid.

Give a word equation for the following reaction.

Two gases which combine to give a solid.

Give a word equation for the following reaction.

A compound which on heating shows – colour change from brown to yellow.

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.