Question

Va rog cât de repede se poate

Answer 1

1.

m.apa = 280 g , md = 60 g

stim ca w% = mdx100/ms

stim ca ms = md+m.apa

= 280+60 = 340 g sol

=> w% = 60x100/340 = 17,6%

2.

principiu , la fel ca la 1.

300 mL apa = 300 g apa

3.

ms1 = 160 g , w1% = 3%

m.apa = 140 g

stim ca w% = mdx100/ms

stim ca ms.final = ms1 + m.apa.adaugata

= 160 + 140 = 300 g sol

md = ms1xw1%/100 = 160x3/100 = 4,8 g

=> w%.final = mdx100/ms.final

= 4,8x100/300 = 1,6%

4.

principiu , la fel ca la 3.

170 mL apa = 170 g apa

5.

ms1 = 60 g , w1% = 1%

=> md1 = ms1xw1%/100

= 60x1/100 = 0,6 g

md.adaugat = 4 g

=> w%.final = md.finalx100/ms.final

md.final = md1 + md.adaugat = 0,6 + 4 = 4,6 g

ms.final = ms1 + md.adaugat = 60 + 4 = 64 g

=> w%.final = 4,6x100/64 = 7,2% (aproximativ)