Question

What is the molarity of a solution that contains `"5 moles"` of solute dissolved in a solution that is `"975 mL"`?

Answer 1

The molarity of the solution is `"5.1 mol/L"`.

The solution is said to be `"5.1 molar"`.

The shorthand way to indicate molarity is `"5.1 M"`, which is pronounced `"5.1 molar"`, and is how it is written on the label of its container.

Explanation:

`"Molarity (M)"=("moles of solute")/("liters of solution")`

The volume of the solution is given in mL. The volume is required to be in liters, so `"975 mL"` must be converted to liters.

`"1 L=1000 mL"`

`975color(red)cancel(color(black)("mL"))xx(1"L")/(1000color(red)cancel(color(black)("mL")))="0.975 L"`

`"Molarity (M)"=(5.0"mol")/(0.975"L")="5.1 mol/L"` rounded to two significant figures