Question

Salut , ma ajuta cineva si pe mine cu 3 probleme la chimie

Answer 1

26.

ms1 = 200 g , c% = 30% , m.apa = 300 g

stim ca c% = mdx100/ms

=> md = ms1xc%1/100 = 200x30/100 = 60 g

=> ms2 = ms1 + m.apa

=> c%.fianala = mdx100/(ms1+m.apa)

=> c% = 60x100/500 = 12% => d)

27.

ms1 = 20 g , c%1 = 10%

ms2 = 30 g , c%2 = 20%

stim ca c% =mdx100/ms

=> md1 = ms1xc%1/100 = 20x10/100 = 2 g

=> md2 = ms2xc%2/100 = 30x20/100 = 6 g

=> ms.tot = ms1 + ms2 = 20 + 30 = 50 g

=> md.tot = md1 + md2 = 2 + 6 = 8g

=> c%.final = md.totx100/ms.tot = 8x100/50 = 16% => a)

28.

stimca Cm = md / M.molec. x Vs si ca  1 dm3 = 1 L

=> md = Cm x M.molec. x Vs = 3 x 56 x 0,5 = 84 g KOH => b)