Secondary School (English Medium) (5 to 8) कक्षा ७ - CBSE Question Bank Solutions

Which of the following is a chemical change?

A chemical change may involve –

Which of the following is/are true when milk changes into curd?

1. Its state is changed from liquid to semi solid.
2. It changes colour.
3. It changes taste.
4. The change cannot be reversed.

Choose the correct option from below:

Which of the following statement is incorrect for a chemical reaction?

State whether the following statement is true or false:

When a candle burns, both physical and chemical changes take place.

Melting of wax is a change where a solid changes to liquid state. Give one more such change which you observe in your surroundings

Iron benches kept in lawns and gardens get____________. It is a _________ change because a new _________ is formed.

Classify the following processes into physical or chemical changes:

1. Beating of aluminium metal to make aluminium foil.
2. Digestion of food.
3. Cutting of a log of wood into pieces.
4. Burning of crackers.

Write word equations for two chemical reactions with the help of materials given in the box.

Give two examples for the following case:

Chemical changes

Give an example of a chemical reaction for the following situation:

A change in colour is observed

If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.

Can you change rust back into iron by some simple method?

If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.

Do you think formation of rust from iron is a chemical change?

A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.

What changes do you expect?

A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.

Are these changes chemical in nature?

A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.

Write a word equation for the chemical change, if any.

Out of the given definitions, which is the most appropriate definition of climate?

Which of the following briefly describes the desert climate?

Paheli went to a wildlife sanctuary where she saw dense vegetation of trees, shrubs, herbs and also a variety of animals like monkeys, birds, elephants, snakes, frogs, etc. The most likely location of this sanctuary is in the –

Read the following environmental conditions of tropical rain forests.

1. Hot and humid climate
2. Unequal lengths of day and night
3. Abundant rain fall
4. Abundant light and moisture

Identify the conditions from the above list that are responsible for the presence of large number of plants and animals in tropical rain forests.