Question

va rog, URGEEEEEENT !!!! Dau CORONITA !!! ​

Answer 1

1)

m.apa = 30g, md = 20g

ms = md+m.apa = 30+20 = 50g

c% = mdx100/ms = 20x100/50 = 40%

2)

c% = 8%, m.apa = 110,4 g

c% = mdx100/ms

ms = md+m.apa

=> 8 = 100md/(110,4+md)

=> md = 883,2/92 = 9,6 g

=> ms = 110,4 + 9,6 = 120 g

3)

ms1 = 80g, c1% = 16%

ms2 = 320g, c2% = 20%

ms.final = ms1 + ms2 = 80+320 = 400g

din c% =>

md1 = ms1xc1/100 = 80x16/100 = 12,8g

md2 = ms2xc2/100 = 320x20/100 = 64g

=> md.final = md1+md2 = 12,5+64 = 76,8g

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

= 76,8x100/400 = 19,2%

4)

ms1 = 500g, c1% = 6%

pentru mama:

c2% = 4%

a adugat apa in plus pentru al mai dilua

md = ms1xc1/100 = 500x6/100 = 30g

=> ms2 = ms1+m.apa.adaugata (a) = 500+a

=> 4 = 30x100/(500+a)

=> a = 1000/4 = 250 g apa adugata

pentru mine:

mai adaug zahar suplimentar (adica cresc masa dizolvatului)

c2% = 15%

md1= ms1xc1/100 = 500x6/100 = 30g

md.final = md1+a, a = masa de dizolvat adaugat

ms.final = ms1+a = 500+a

15 = (30+a)100/(500+a)

=> a = 4500/85 = 52,94 g zahar adugat