根据n=
求的Na2CO3?10H2O的物质的量n=m M
=0.005mol,则n(Na+)=0.01mol,故Na+ 物质的量浓度为C=1.43g 286g/mol
=n V
=0.1mol/L;0.01mol 0.1L
设加入蒸馏水的体积为XL,根据C(Na+)=0.1mol/L可知C(Na2CO3)=0.05mol/L,根据C浓V浓=C稀V稀可知:0.05mol/L×0.02L=0.004mol/L×(0.02L+XL),解得:X=0.23L,即230ml.
故答案为:0.1mol/L;230ml.