A sample of sulfurous acid (H2SO3) has a mass of 1.31 g. a) How many H+ ions are present?
b) How many SO32- ions are present?
c) What is the mass in grams of one formula unit of H2SO3?

a) 2 (H+) ions

b) 1 (SO3²-) ions

c) 1.36 × 10^-22 grams.

Explanation:

According to this question, sulfurous acid has a chemical formula; H2SO3. It is made up of hydrogen and sulfite ion. Hydrogen ion (H+) is the cation while sulfite ion (SO32-) is the anion.

Based on the chemical formula, there are 2 moles of hydrogen ions that reacts with 1 mole of sulfite ion as follows:

2H+ + SO3²- → H2SO3

Hence;

- there are 2 hydrogen ions (2H+) present in H2SO3.

- there is 1 sulfite ion (SO3²-) present in H2SO3.

c) The mass of one formula unit of H2SO3 is calculated thus:

= 1.008 (2) + 32.065 + 15.999(3)

= 2.016 + 32.065 + 47.997

= 82.08 a.m.u

Since, 1 gram is = 6.02 x 10^23 a.m.u

82.08 a.m.u = 82.08/6.02 × 10^-23

= 13.6 × 10^-23

= 1.36 × 10^-22 grams.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)