1. md = 19,6g , ms = 2 kg = 2000g
c% = mdx100/ms = 19,6x100/2000 = 0,98%
2.
md = 2,5g , m.apa = 40,5g
stim ca ms = md+m.apa = 2,5+40,5 = 43g sol.
c% = mdx100/ms = 2,5x100/43 = 5,82%
3.
ms = 800g, c%= 40%
c% = mdx100/ms
=> md = msxc%/100 = 800x40/100 = 320 g NaOH