Carbon dioxide obtained by the action of an excess of hydrochloric acid on 200 g of calcium carbonate is passed through a solution containing 60 g of sodium hydroxide. determine the composition and mass of the resulting salt.
1. We write down the equation of the reaction of hydrochloric acid and calcium carbonate:
2HCl + CaCO3 = CaCl2 + H2O + CO2;
2.Calculate the chemical amount of calcium carbonate:
n (CaCO3) = m (CaCO3): M (CaCO3);
M (CaCO3) = 40 + 12 + 3 * 16 = 100 g / mol;
n (CaCO3) = 200: 100 = 2 mol;
3. find the chemical amount of carbon dioxide:
n (CO2) = n (CaCO3) = 2 mol,
4.Calculate the chemical amount of sodium hydroxide:
n (NaOH) = m (NaOH): M (NaOH);
M (NaOH) = 23 + 16 + 1 = 40 g / mol;
n (NaOH) = 60: 40 = 1.5 mol
5.from the calculations of chemical quantities, it can be seen that sodium hydroxide is in short supply, therefore, as a result of the reaction, an acidic salt will be formed – sodium bicarbonate:
NaOH + CO2 = NaHCO3;
6. find the mass of bicarbonate:
n (NaHCO3) = n (NaOH) = 1.5 mol;
m (NaHCO3) = n (NaHCO3) * M (NaHCO3);
M (NaHCO3) = 23 + 1 + 12 + 3 * 16 = 84 g / mol;
m (NaHCO3) = 1.5 * 84 = 126 g.
Answer: 126 g NaHCO3.