Question

Determine the number of moles of calcium carbonate with 10% impurities, which reacts with 21.9 g of hydrochloric acid.

Answer 1

Answer: 0.297 moles of calcium carbonate.

Solution:

Number of moles of HCl =
`\frac{\text{given mass}}{\text{molecular mass}}=(21.9 g)/(36.5 g/mol)=0.6` moles

`CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2`

According to reaction

Two moles of HCl are reacting with one mole of
`CaCO_3`, then 0.6 moles of HCl will react with:

=
`(1)/(2)* 0.6\text{moles of}CaCO_3`

Moles of calcium carbonate reacted = 0.3 moles

In 0.3 moles of calcium carbonate 10% impurities is present i.e.

`=0.3* (10)/(100)=0.03 mol` of impurity.

Actual number of moles of calcium carbonate reacted = 0.3 - 0.003 = 0.297 moles.