Answer :
Answer:
= 0.01 % m/v
Explanation:
From the information given we first need to understand the meaning of;
10% m/v, it means 10% mass to volume ratio
That is; 10g of a solute (NaCl) are present in 100 mL of solution (water)
Therefore;
First, we can determine the concentration of the initial solution of NaCl
Concentration = Moles ÷ Volume
But, Moles = Mass ÷ Molar mass
Molar mass of NaCl = 58.44 g/mol
Moles = 10 g ÷ 58.44 g/mol
= 0.171 moles
Thus;
Concentration= 0.171 moles × 0.1 L
= 0.0171 M
Second, we can determine the concentration of the solution after dilution.
Using dilution equation;
M1V1 = M2V2
M2 = M1V1 ÷ V2
= (0.0171 M×0.05 L) ÷ 0.5 L
= 0.00171 M
Therefore, the concentration after dilution is 0.00171 M
Thirdly, we find the % by mass to volume ratio
Concentration = 0.00171 M ( means 0.00171 moles/liter)
Mass of NaCl = 0.00171 moles × 58.44 g/mol
= 0.09993
= 0.1 g
0.1 g = 1000 mL(1 L) (0.1 g/L)
To get % m/v we find the Mass in 100 mL will be;
= (0.1 g× 100 mL)÷ 1000 mL
= 0.01 % m/v