设石灰石中CaCO3的质量为x,稀盐酸中含HCl的质量为y,
CaCO3+2HCl═CaCl2+H2O+CO2↑
100 73 111 44
x y
111x 100
44x 100
x+100g=
÷20%+111x 100
解得:x=20g44x 100
=100 20g
y=14.6g73 y
稀盐酸中溶质的质量分数=
×100%=14.6%.14.6g 100g
答:所用稀盐酸中溶质的质量分数为14.6%.