Question

1) Sa se calculeze concentratia procentuala a solutiei obtinute daca la 2grame acid sulfuric corespund 10 grame apa.

2) Daca 2 kilograme solutie de concentratie 20% piper prin evaporarea a 500 grame apa.Care este concentratia finala a solutiei?

Answer 1

1) ms = 10+2 = 12 g
md = 2
=> c% = md/ms * 100 = 2/12 * 100 = 16,666 %
2) md = c*ms/100= 2000*20/100 = 400 g piper
ms1 = md + m apa 1  => m apa 1 = 2000 - 400 = 1600 g
m apa 2 = m apa 1 - 500 = 1100 g apa
ms 2 = md + m apa 2 = 1100 + 400 = 1500 g 
c% = 400/1500 * 100 = 26,666%