Question

把铝,镁混合物7.8g溶于2.0L,5mol/L的盐酸中,反应后盐酸的浓度变为4.6mol/L

Answer 1

1 （5-4.6）*2=0.8 mol

2 Mg + 2 HCl = MgCl2 +2 H2

m 2m 2m

2Al + 6HCl = 2AlCl3 + 3H2

2n 6n 3n

2m+6n=0.8

24m+54n=7.8

解得m=0.1

n=0.1

所以2.4g 镁,5.4g 铝

3 2m+3n=0.5 mol =11.2L