Matter and Its Composition — CHEMISTRY STD 7 — Question

State whether the following is physical or chemical changes.
respiration in living beings —

What do you understand by the following terms : Distillation

Answer the question put against the following constituents of air :
Carbon dioxide : “Although carbon dioxide plays no role in respiration, all life would come to an end if there is no carbon dioxide in air.” Support this statement with relevant facts.

An atom has 13 protons and 14 neutrons.
What is the atomic number of the atom ?

What are the chemicals used in a soda-acid fire extinguisher ?

State whether the following is physical or chemical changes.
glowing of a bulb -

Hard water is unfit for washing purposes.

Name a metal which is poor conductor of electricity :

Define the term acid rain.

Give three examples of each molecules which has:Different kind of atoms