Question

Trộn 100g dd NaOH a% với 50g dd NaOH 10% được dd NaOH 7,5% . Xác định a%

Answer 1

mNaOH(a%0=100.a/100=a

mNaOH(10%0=50.10/100=5

C%NaOH(7,5)=\(\frac{5+a}{100+50}.100=7,5\)=>a=6,25

Answer 2

K/l NaOh trong dd a%:

m=a/100.100=a(g)

mNaoh trong dd 10%:

50.10/100=5(g)

C% dd naoh 7,5%:

(5+a)/150.100=7,5

Suy ra a=6,25(%)

Answer 3

Answer 4

\(m_{NaOH.10\%}=\frac{50.10}{100}=5\left(g\right)\\ m_{NaOH.a\%}=\frac{100.a}{100}=a\left(g\right)\\ C\%_{ddNaOH.7,5\%}=\frac{a+5}{150}.100=7,5\\ \Leftrightarrow a=\left(\frac{7,5}{100}.150\right)-5=6,25\left(\%\right)\)

Answer 5

mNaOH ( a%) = a (g)

mNaOH ( 10%) = 5 g

mdd = 100 + 50 = 150 g

mNaOH = a + 5 (g)

C%NaOH = (a+5)/150*100% = 7.5%

=> a = 6.25