Question

Student A completes a similar experiment but is given different initial values for volume and concentration in Task 1. The student has lost their worksheet but remembers that they prepared a 50 mL solution, however, the concentration of that solution has been forgotten. In order to find the concentration of the solution, Student A evaporates all of the water from the solution and is left with 1.46 g of sodium chloride. What concentration was student A initially assigned? Within your calculations include an explanation of your steps.

Answer 1

1. Molar concentration is

$$C=n/V$$

n - number of moles of a substance contained in a solution, mol

V - solution volume, L

2. $n=m/M$

m - mass, g

M - molar mass, g/mol

$$n=1.46/58.5=0.025 mol$$

3. Molar concentration is

$$C=0.025/0.05=0.5 M$$