Limestone rock contains solid calcium carbonate that can react with
acid to give products. In one experiment, 1.452 g of limestone rock is
pulverised and then treated with 25.00 mL of 1.035 M HCl solution.
After the reaction is completed, the resulting mixture is still acidic. The
excess acid then requires 15.25 mL of 0.1010 M NaOH for
neutralisation. Assuming that calcium carbonate is the only substance
in limestone rock that reacts with HCl solution:
i. Write the balanced chemical equation and net ionic equation for
the reaction that occurs between calcium carbonate and
hydrochloric acid.
[2 marks]
10I don't understand this 10
FAC 0015 I don't understand this number either
CaCO3 + 2HCl ==> CaCl2 + CO2 + H2O
CO3^2- + 2H^+ ==> CO2 + H2O
ii. Calculate the number of moles of hydrochloric acid that reacts
with calcium carbonate.
[3 marks]
mols HCl added initially - mols HCl added in excess = mols HCl reacted with sample.
Initial mols HCl added = M HCl x L HCl = ?.
mols HCl in excess = mols NaOH x L NaOH = ?
Subtract to find mols HCl used in the reaction.
iii. Calculate the percent by mass of calcium carbonate in the rock.
Convert mols HCl used in the reaction to mols CaCO3 reacted. That is mols HCl x (1 mol CaCO3/2 mols HCl) = ?
Then grams CaCO3 = mols CaCO3 x molar mass CaCO3.
Finally, %CaCO3 = (g CaCO3/mass initial sample)*100 = ?
Limestone rock contains solid calcium carbonate that can react with
acid to give products. In one experiment, 1.452 g of limestone rock is
pulverised and then treated with 25.00 mL of 1.035 M HCl solution.
After the reaction is completed, the resulting mixture is still acidic. The
excess acid then requires 15.25 mL of 0.1010 M NaOH for
neutralisation. Assuming that calcium carbonate is the only substance
in limestone rock that reacts with HCl solution:
i. Write the balanced chemical equation and net ionic equation for
the reaction that occurs between calcium carbonate and
hydrochloric acid.
[2 marks]
10
FAC 0015
ii. Calculate the number of moles of hydrochloric acid that reacts
with calcium carbonate.
[3 marks]
iii. Calculate the percent by mass of calcium carbonate in the rock.
1 answer