Matter — CHEMISTRY STD 6 — Question

Define: Atom

State the important uses of water in our daily life.

Define a physical change and a chemical change. Give two examples of each.

Name the elements which form water.
How will you justify that water is a compound?

Write a short note on development of Chemistry- a historical perspective.

Give two uses of the following component present in air:
water vapour

An atom of an element is denoted by a “symbol” Explain the meaning of the term ‘symbol’. State a reason for representing the following element by its symbol.

Helium by ‘He’

Give reasons for the following
All medicines must be taken under proper doctors' supervision and in the correct dose.

Draw a labelled diagram of an atom including its nucleus, orbits & their contents.

Give two reasons to explain whether the following are physical or chemical changes.
Glowing of an electric bulb