Question

vă roggg multtt acum trebuie sa le facem ,vă rogg nu am mult timppp ​

Answer 1

3.

A.

ms = md+m.apa = 25+125 = 150g sol.

c% = mdx100/ms

= 25x100/150 = 16,67%

B.

ms = 300g, c% = 20%

c% = mdx100/ms

=> md = msxc%/100

= 300x20/100 = 60 g zahar

C.

ms1 = 300g, c1% = 10%

ms2 =?g , c2% = 25%

c% = mdx100/ms

=> md1 = ms1xc1/100

= 300x10/100 = 30g acid clorhidric dizolvat

notam m.apa.evap. = a

ms2 = ms1 - a

c2% = mdx100/ms2

=> 25 = 30x100/(300-a)

=> a = m.apa.evap. = 4500/25 = 180 g apa evaporata

facem proba de calcul

md = 30g

ms2 = 300-180 = 120g

c2% = 30x100/120 = 25%, deci verifica calculul de mai sus

D.

ms1 = 200g, c1% = 40%

ms2 = 300g , c2% = 20%

ms.final = ms1 + ms2 = 200+300 = 500g sol. finala

din fiecare sol calc. md

c% = mdx100/ms

=> md1 = ms1xc1%/100

= 200x40/100 = 80 g

=> md2 = ms2xc2%/100

= 300x20/100 = 60g

=> md.final = md1 + md2 = 80+60 = 140 g

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

= 140x100/500 = 28%