Question

A chemist prepares a solution of sodium chloride(NaCl) by measuring out 25.4g of sodium chloride into a 100ml volumetric flask and filling the flask to the mark with water. Calculate the concentration in mol/L of the chemist's sodium chloride solution. Round your answer to significant digits.

Answer 1

Answer: 4 molL-1

Explanation:

Detailed solution is shown in the image attached. The number of moles of NaCl is first obtained. Since the molarity must be in units of molL-1, the volume is divided by 1000 and the formula stated in the solution is applied and the answer is given to one significant figure.

Answer 2

Answer:4.3Mol/L

Explanation:

Mass concentration = Molar Concentration × Molar mass

Mass concentration of NaCl = 25.4/0.1L = 254g/L

Molar Mass of NaCl = 58.5g/mol

Then Molar Conc = Mass Conc / Molar Mass

= 254g/L / 58.5 g/mol

= 4.3 Mol/L