Solid sodium carbonate reacts with aqueous hydrochloric acid to form aqueous sodium chloride, carbon dioxide and water.

Na₂CO₃ + 2HCl → 2NaCl + CO₂ + H₂O

a. Rewrite this equation to include state symbols.

b. Calculate the number of moles of hydrochloric acid required to react exactly with 4.15 g of sodium carbonate.
(A_r values: C = 12.0, Na = 23.0, O = 16.0)

c. Define the term mole.

d. An aqueous solution of 25.0 cm³ sodium carbonate of concentration 0.0200 mol dm^–3 is titrated with hydrochloric acid. The volume of hydrochloric acid required to exactly react with the sodium carbonate is 12.50 cm^3.
i. Calculate the number of moles of sodium carbonate present in the solution of sodium carbonate.
ii. Calculate the concentration of the hydrochloric acid.

e. How many moles of carbon dioxide are produced when 0.2 mol of sodium carbonate reacts with excess hydrochloric acid?

f. Calculate the volume of this number of moles of carbon dioxide at r.t.p. (1 mol of gas occupies 24 dm³ at r.t.p.)