Question

Ideal Gas Laws: Needs explanation and steps to derived the answers Thank you.

The reaction between sodium carbonate and hydrochloric acid yields carbonic acid and a salt. Carbonic acid further decomposes into water and carbon dioxide. In an experiment, you initially have 80 ml of a .70 M solution of sodium carbonate and .10 L of .65 M solution of hydrochloric acid. The two solutions are mixed and are allowed to react and the gas product is collected in an empty balloon. Assuming that initially the volume of gas in the balloon is zero. The reaction forms gaseous carbon dioxide and liquid water. What will be the volume of the balloon (neglect the volume of liquid water) after the reaction is complete under TSP conditions? (Assume that the balloon does not significantly compress the gas).

Answer 1

Na2CO3 + 2HCl -----> H2CO3 + 2NaCl

H2CO3 ----> CO2 + H2O

mol Na2CO3= 0.7M x 0.08L= 0.056mol

mol HCl= 0.65M x 0.1L= 0.065mol

1mol Na2CO3 -------- 2 mol HCl

0.056mol Na2CO3 ------- x= 0.112 mol HCl ----> the Na2CO3 is in excess, HCl is the limiting reactant.

2 mol HCl produces 1 mol of H2CO3 who descomposes into 1 mol of CO2, so we can say:

2 mol HCl -------- 1 mol CO2

0.065mol HCl ------ x= 0.0325 mol CO2

Volume= 0.0325 mol x 0.082L.atm/mol.K x 273K/1atm = 0.728L