Question

1) Intr-un pahar se afla 20 grame de zahar.Ce concentratie va avea solutia prin adaugarea altei solutii formata din 500 grame apa si 36 grame zahar?

2) Ce concentratie va avea solutia rezultanta din evaporarea a 150 grame apa din 300 grame solutie de concentratie initiala 30%?

3) Peste 80 grame solutie de concentratie 155 se adauga 20 grame apa.Ce concentratie are solutia obtinuta astfel?

4) ce concentratie va avea solutia rezultata prin adaugarea a 450 grame de apa peste 300 grame solutie de concentratia initiala de 5%?

VA ROGGG E URGENTTTT!!!❤️❤️❤️❤️

Answer 1

1)

md1 = 20g

m.apa = 500g , md = 36g zahar

ms.finala = m.apa + md + md1 = 500+20+36 = 556 g sol.

md.final = md1+md = 56 g

c% = md.finalx100/ms.finala

= 56x100/556 = 10,1% rotunjit

2)

ms.final = ms.initial - m.apa evaporata = 300-150 = 150 g sol

c% = mdx100/ms

=> md = msxc%/100 = 300x30/100 = 90 g

=> c%.finala = mdx100/ms.finala

= 90x100/150 = 60%

3)

ms1 = 80 g. c1% = 15%

ms.finala = ms1 + m.apa.adaugata = 80+20 = 100 g sol.

md = ms1xc1%/100

= 80x15/100 = 12 g

=> c%.finala = mdx100/ms.finala

= 12x100/100 = 12%

4)

ms = 300g, c% = 5%

din c% = md = msxc%/100

= 300x5/100 = 15 g

m.apa = 450 g

ms1 = ms + mapa.adaugata

= 300+450 = 750 g sol.

c%.finala = mdx100/ms.finala

= 15x100/750 = 2%