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Ajutoor
EX 2 şi 6 merci DAU COROANA!
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AjutoorEX 2 Şi 6 Merci DAU COROANAurgeent class=

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2. a) calculezi md=c*ms/100  => md=37.5g
adaugi 200g apa, deci ms=150+200=350g
calculezi c=md/ms *100 => c=10,71%
b) calculezi md=3.2g
adaugi sare deci creste md=3,2+8=11,2g (creste si ms=80+8=88)
calculezi c=12,72%
c) scoti md=33,75g
adaugi apa si sare deci md=48,75g si ms=340g
c=14,33%
6. calculezi md pt prima md=20g
adaugi sarea, deci md=20+x iar ms=200+x
in formula concentratiei inlocuiesti datele si iti da 25=20+x/200+x *100
dupa rezolvarea calculelor va rezulta x=40g. Deci mai trebuie adaugate 40g

2. a) mH₂O = 200g
msi = 150g sol.
C = 25%

C = md/ms×100 ⇒ md = C×ms/100  = 25×150/100 = 37,5g 

msf = msi + mH₂O adaugata = 150+200 = 350g

Cf = mdi/msf×100 = 37,5/350×100 = 10,714%

b) md  ad= 8g NaCl
msi = 80g
C=4%

Ci = mdi/msi×100 ⇒ mdi = Ci×msi/100 = 4×80/100 = 3,2g NaCl

mdf = mdi+md ad = 3,2+8 = 11,2g
msf = msi+md ad = 80+8 = 88g

Cf = mdf/msf×100 = 11,2/88×100 = 12,72%

c) md ad = 15g NaCl
m H₂O ad = 100g

msi = 225g NaCl
Ci=15%

Ci = mdi/msi×100 ⇒ mdi = Ci×msi/100 = 15×225/100 = 33,75g NaCl

mdf = mdi+md ad  = 33,75+15 = 48,75
msf = msi+md ad + m H₂O ad = 225+15+100 = 340g sol. NaCl

Cf = mdf/msf×100 = 48,75/340×100 = 14,33%

6.md ad = ? g NaCl

msi = 200g
Ci = 10%
Cf = 25%

Ci = mdi/msi×100 ⇒ mdi = 10×200/100 = 20g NaCl

msi = mdi+mH₂O =⇒ mH₂O = msi-mdi = 200-20 = 180g

Cf×mH₂O = mdf(100-C)
25×180 = mdf(100-25)
4500 = 75mdf ⇒ mdf = 4500/75 = 60g NaCl

md NaCl ad = mdf-mdi = 60-20 = 40g