Iron and oxygen react together to make iron (iii) oxide (rust). you know that this is a chemical reaction and not a nuclear reaction because:

a large amount of heat is produced by the reaction
the individual atoms are rearranged but do not change identity
new products are formed as a result of the reaction
the rust has a greater mass than the iron and oxygen used to produce it

The individual atoms are rearranged but do not change identity

Explanation:

Hi, identity of an element is given by the amount of protons it has in its nucleous: two different elements must have different amounts of protons.

During a chemica reaction, such as the one between oxygen and iron, the atoms of the two elements create bonds but no a new element: they identities remain intact, so this is not a nuclear reaction

answer

i think the answer is a) as air pressure in an area increases, the density of the gas particles in that area decreases.

hope it

- lead + phosphoric acid = hydrogen + lead(ii) phosphate