Question

What is the molarity of a sodium chloride solution that has 2.0 mol of

sodium chloride dissolved in 0.25 L of water? Answer to two
significant figures.

Answer 1

`\boxed {\boxed {\sf 8.0 \ M \ NaCl}}`

Step-by-step explanation:

Molarity is a measure of concentration in moles per liter, therefore the formula is:

`molarity= (moles \ of \ solute)/(lites \ of \ solution)`

There are 2.0 moles of solute or sodium chloride dissolved in 0.25 liters of water or solution.

• moles of solute = 2.0 mol NaCl
• liters of solution = 0.25 L

Substitute these values into the formula.

`molarity= ( 2.0 \ mol \ NaCl)/(0.25 \ L)`

Divide.

`molarity=8 \ mol \ NaCl / L`

Molarity is measured in molars or M. 1 molar is equal to 1 mole per liter, so our answer is equal to 8 molars.

`molarity= 8 \ M \ NaCl`

The original measurements of moles and liters have 2 significant figures, so our answer must have the same. For the number we calculated, that is the tenths place. There are no numbers to round, so we add a 0 in the tenths place.

`molarity= 8.0 \ M \ NaCl`

The molarity of the solution is 8.0 M NaCl.