Question

4 si 7 la chimie!Ajutor!

Answer 1

4)
c = md*100/ms
md = ms*c/100 = 200*10/100 = 20 g zahăr
ms = md + m dizolvant
m dizolvant = 200-20 = 180 g
7)
c = md*100/ms
md1 = 30*100/100 = 30g
md2 = 50*20/100 = 10 g
md3 = 40*100/100 = 40 g 
md4 = md1+md2+md3 = 30+10+40 = 80 g
ms4 = ms1+ms2+ms3 = 100+50+100 = 250 g soluție
c4 = 80/250*100 = 32%