V1.apa = 20 L
p.apa = 1 g/cm3 sau 1 kg/m3
md = 2 kg
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c1% = ?%
c2% = ?%, V2.apa = 10 L
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m1.apa = pxV1.apa = 20x1 = 20 kg
ms1 = md+m1.apa = 2+20 = 22 kg
c1% = mdx100/ms1 = 2x100/22 = 9,1%
m2.apa = pxV2.apa = 1x10 = 10 kg
ms2 = ms1 + m2apa = 22 + 10 = 32 kg sol. finala
c2% = mdx100/ms2 = 2x100/32 = 6,25%