25.75 mL of a hydrochloric acid solution reacts completely with a solid sample of magnesium carbonate producing 170.8 mL of CO2 which is collected over water at 24.00°C and 731.0 torr total pressure. The vapor pressure of water at 24.00°C is 22.4 torr.
2 HCl(aq) + MgCO3(s) → CO2(g) + H2O(l) + MgCl2(aq)
What is the molarity of the HCl solution?
PV = nRT and solve for n = number of mols.
P = (731.0-22.4)/760
V = 0.1708 L
R = 0.08206
T = 273 + 24 = ?
solve for n. Let's call that y
MgCO3 + 2HCl ==> H2O + CO2 + MgCl2
You know mols CO2 = y
Therefore, mols MgCO3 must be y.
mols HCl must be twice that.
MHCl = mols HCl/L HCl.