124.4g*5.87%=7.3g
CaCO3+2HCl==CaCl2+H2O+CO2↑
100 73
x 7.3g
100/x=73/7.3g
x=10g
该样品中含杂质碳酸钙的质量分数
10g/80g*100%=12.5%