Answer:
The final concentration in molarity (M) is 0.4
Explanation:
K₂SO₄ (Potassium sulfate) - Molar mass = 174.3 g/m
First of all, we have 200 mL, 0.4 M
Molarity . volume = mol
(mol/L) . L = mol → 0.4 mol/L . 0.2L = 0.08 moles of salt, in the beginning.
In second situation we have 7% m/v of salt, which means that in 100 mL of solution, we have 7 grams of solute.
7 g / 174.3 g/m = 0.040 moles in 100 mL
Let's think the rule of three:
In 100 mL we have 0.04 moles of salt
in 400 mL we have (400 . 0.04)/100 = 0.16 moles
1st situation: 0.08 moles of salt
2nd situation: 0.16 moles of salt
Total moles = 0.08 + 0.16 = 0.24 moles
Total volume = 200 mL + 400 mL = 600 mL
Molarity = mol/L
0.24 mol / 0.6L = 0.4M
