Question

Question 44
Fill in the blanks

(a) In a chemical reaction, the sum of the masses of the reactants and products remains unchanged. This is called ___.

(b) A group of atoms carrying a fixed charge on them is called ___.

(c) The formula unit mass of $C{a}_3(P{O}_4{)}_2$ is ____.

(d) Formula of sodium carbonate is ___ and that of ammonium sulphate is ____.

Answer 1

(a) Law of conservation of mass
Law of conservation of mass states that mass can neither be created nor be destroyed, hence the mass of reactants = mass of products

(b) Polyatomic ion
Example: $P{O}_4^{3-}$

(c) (3 x atomic mass of Ca) + (2 x atomic mass of phosphorus) + (8 x atomic mass of Oxygen)
($3\times 40+2\times 31+8\times 16=310$)

(d) $N{a}_{2}C{O}_{3}and(N{H}_4{)}_{2}S{O}_4$