1.
m(NaCl)=1000g*0.9%=9g
M=9g/18%=50g
m(H2O)=50g-9g=41g
2.
m(NaCl)=100g*10%=10g
(1)
m=10g/(10%*2)=50g
m(H2O)=100g-50g=50g
蒸发水50g
(2)
m(H2O)=100g-10g=90g
设有食盐 x g
x/(x+90)=20%
0.2*(x+90)=x
x=22.5
∴应加入22.5-10=12.5g
1.
m(NaCl)=1000g*0.9%=9g
M=9g/18%=50g
m(H2O)=50g-9g=41g
2.
m(NaCl)=100g*10%=10g
(1)
m=10g/(10%*2)=50g
m(H2O)=100g-50g=50g
蒸发水50g
(2)
m(H2O)=100g-10g=90g
设有食盐 x g
x/(x+90)=20%
0.2*(x+90)=x
x=22.5
∴应加入22.5-10=12.5g