Question

Din 150g solutie de concentratie 5% s-au evaporat 25g apa.Determina concentratia solutiei obtinute!Repede va rog mult!

Answer 1

$md = ms \times \frac{c}{100} = \frac{150 \times 5}{100} = \frac{75}{10} = 7,5 \: g \\ \\ m \: apa = ms - md \\ \\ m \: apa = 150 - 7,5 = 142,5 \: g \\ \\ 142,5 - 25 \: g \: evaporate = 117,5 \: g \\ \\ ms \: final = md + apa \\ \\ ms = 7,5 + 117,5 \\ \\ ms = 125 \: g \\ \\ c \: final = ( \frac{md}{ms}) \times 100 \\ \\ c \: final = ( \frac{7,5}{125}) \times 100 \\ \\ c \: final = \frac{725}{125} \\ \\ c \: final =6 \: \%$