Answer:
(a):Valency is the measure of the capacity of an atom of a single element to react and combine with particular numbers of atoms of another element.
(b):
Valency of calcium:+2
Valency of Iron:Iron exhibits 2 valence states of +2 and +3.
Valency of hydroxl:-1
Valency of Nitrate:-1
Explanation:
A solute is a substance that dissolves into another substance , and forms a solution.
When temperature increases pressure also increases.
When temperature decreases pressure decreases.
That is why you have low tire pressure when it’s cold out
I think the best answer that will describe chemical change is the first option. During a chemical change, b<span>oth the identity and the properties of a substance change because new substances are being formed by a chemical reaction. An example is rusting of steel</span>
