Question

Proszę o rozwiązanie zadań z załącznika. :P

Answer 1

zadanie 1

n = 6moli

V = 2dm³

 

cm = n/V

 

cm = 6moli/2dm³ 0 3mol/dm³

 

zadanie 2

V = 0,4dm³

cm = 0.2mol/dm³

M NaCl = 58,8g/mol

 

cm = n/V => n = cmV

 

n = 0,4dm³ x 0,2mol/dm³ = 0,08mola

 

m = nM

 

m = 0,08mola x 58,8g/mol = 4,704g

 

zadanie 3

cp = 10%

ms = ?

 

cp = ms/mr x 100% = ms/m wody + ms x 100%

 

10% = ms/200g + ms x 100%

0,1 = ms/200g + ms

20g + 0,1ms = ms

0,9ms = 20g

ms ≈ 22,22g

 

zadanie 4

d = 0,9g/cm³ = 0,9kg/dm³

V = 1dm³

cp = 45%

 

ms = mr x cp/100%

mr = dV

 

ms = 0,9kg/dm³ x 1dm³ x 45%/100% = 0,405kg = 405g

 

m wody = 900g - 405g = 495g

 

zadanie 5

 

 

cm = cp x d/M x 100%

 

cp NaOH = 40%

M NaOH = 40g/mol

d = 1,43g/cm³ = 1430g/dm³

 

cm NaOH = 40% x 1430g/dm³/40g/mol x 100% = 14,3mol/dm³

 

cp KOH = 40%

M KOH = 56g/mol

d = 1,4g/cm³ = 1400g/dm³

 

cm KOH = 40% x 1400g/dm³/56g/mol x 100% = 10mol/dm³

 

zadanie 6

M H₂O₂ = 34g/mol

cm = 12mol/dm³

d = 1,13g/cm³ = 1130g/dm³

 

cp = cm x M/d x 100%

 

cp = 12mo/dm³ x 34g/mol/1130g/dm³ x 100% = 36,1%

 

zadanie 7

m wody = 5kg = 5000g

ms = 1kg = 1000g

mr = 5000g + 1000g = 6000g

 

cp = ms/mr x 100%

 

cp = 1000g/6000g x 100% = 16,7%

 

zadanie8

mr = 300g

cp = 10%

M = 56g/mol

 

ms = cp x mr/100%

 

ms = 10% x  300g/100% = 30g

 

n = m/M

 

n = 30g/56g/mol = 0,54mola

 

 

 

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Litterarum radices amarae sunt, fructus iucundiores

 

Pozdrawiam :)

 

Answer 2

1. 6mol - 2dm^3

     xmol - 1dm^3

x= 6*1/2=3mol

 

Cm= 3mol/dm^3

 

2. 1mol NaCl - 58,5g

     0,2 mol - xg

x= 0,2mol * 58,5g/1mol= 11,7g

 

11,7g - 1dm^3

xg ------ 0,4dm^3

x= 4,68g

 

3. mr = 200g + x

ms = x

Cp = 10%

10% = x * 100%/ (200g + x)   / * 200g + x

10%(200g + x) = x

20 = 0,9x / : 0,9

x= 22,2g

 

4. V= 1000cm^3

d= 0,9g/cm^3

mr= 1000*0,9g= 900g

mw = mr - ms

mw = 900g - 45%*900g= 495g

 

5. d1 = 1,43g/cm^3 V= 1000cm^3 

mr1 = 1430g

ms= 40%*1430g= 572g

1 mol - 40g

x mol - 572g

x= 14,3mol

 

Cm1 = 14,3mol/dm^3 - ten ma większe stężenie molowe

 

d2 = 1,4g/cm^3 V= 1000cm^3 

mr2= 1400g

ms = 40% * 1400g= 560g

1 mol- 56g

x mol - 560g x=10 mol

 

Cm2 = 10mol/dm^3

 

6.

d = 1,13g/cm^3 

V= 1000cm^3

mr= 1130g

1mol - 34g

12mol- xg

x= 408g - ms

 

Cp= 408g*100%/1130g= 36,1%

 

7.

ms = 1kg

d wody = 1g/cm^3

V= 5000cm^3

mw = 5000cm^3 *1g/cm^3= 5000g= 5kg

ms= 5+1=6kg

 

Cp = 1kg*100%/6kg=16,7%

 

8.

ms= 10%*300g= 30g

1 mol - 56g

x mol - 30g

x= 0,54mol - tyle moli potrzeba