Koliko grama neke soli treba dodati u 150g 5% rastvora te soli da bi se dobio 40% rastvor?
w1(soli)=5 % mr1=150 g
m(soli)=w1(soli)*mr1=0.05*150=7.5 g
w2(soli)=40 %
m2(soli)=m1(soli)+x
mr2=mr1+x
w2(soli)=(m1(soli)+x)/(mr1+x)
0.4=(7.5+x)/(150+x)
0.4*150+0.4*x=7.5+x
x-0.4*x=60-7.5
0.6*x=52.5
x=52.5/0.6=87.5 g soli
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Rastvori
w1(soli)=5 % mr1=150 g
m(soli)=w1(soli)*mr1=0.05*150=7.5 g
w2(soli)=40 %
m2(soli)=m1(soli)+x
mr2=mr1+x
w2(soli)=(m1(soli)+x)/(mr1+x)
0.4=(7.5+x)/(150+x)
0.4*150+0.4*x=7.5+x
x-0.4*x=60-7.5
0.6*x=52.5
x=52.5/0.6=87.5 g soli