Air and Atmosphere — CHEMISTRY STD 7 — Question

Name the main metal present in the following:
Chocolate wrappers

Write your observation for the following chemical reaction and name the product formed :
When ammonium chloride is heated with sodium hydroxide.

What problems are caused by the presence ofnitrogen dioxide gas in excessive amount in the air?

Answer the question put against the following constituents of air:
Nitrogen : Explain its significance for plants and animals.

Name three non-metals/radicals which have valency -1, -2, and -3.

By giving an example define endothermic reaction.

A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.
Does the particle have an excess of electrons or a deficiency of electrons ?

Define :-Heterogeneous mixture

Mention two uses of the following metals and non-metals
Aluminium