Question

A saline solution contains 0.800 g of NaCl (molar mass 58.55 g/mol) in 54.6 mL of solution. Calculate the concentration of NaCl in this solution, in units of molarity Express the concentration in molarity to three significant figures.

Answer 1

Answer:

0.25 M

Explanation:

Data obtained from the question include:

Molar mass of NaCl = 58.55 g/mol

Mass of NaCl = 0.800 g

Volume = 54.6 mL

Next, we shall determine the number of mole in 0.800 g of NaCl. This can be obtained as follow:

Molar mass of NaCl = 58.55 g/mol

Mass of NaCl = 0.800 g

Mole of NaCl =?

Mole = mass /Molar mass

Mole of NaCl = 0.8/58.55

Mole of NaCl = 0.0137 mole

Next, we shall convert 54.6 mL to litres (L). This can be obtained as follow:

1000 mL = 1 L

Therefore,

54.6 mL = 54.6 /1000

54.6 mL = 0.0546 L

Finally, we shall determine the molarity of the solution as follow:

Mole of NaCl = 0.0137 mole

Volume = 0.0546 L

Molarity =?

Mol= mole /Volume

Molarity = 0.0137/0.0546

Molarity = 0.25M

Therefore, the molarity of the solution is 0.25 M