Question

What is the molarity (M) of 1 liter of a solution that has 120 g of NaCl dissolved in it?

Answer 1

Answer:

The answer to your question is 2.1

Explanation:

Data

Molarity = 1 l

mass = 120 g of NaCl

moles = ?

Formula

$Molarity = \frac{number of moles}{Volume}$

Process

1.- Calculate the number of moles of NaCl

Molecular weight NaCl = 23 + 35.5 = 58.5 g

2.- Calculate the number of moles using proportions

                           58.5 g of NaCl --------------- 1 mol

                        120.0 g of NaCl  ---------------  x

                             x = ( 120 x 1) / 58.5

                             x = 2.1 moles

3.- Calculate Molarity

Substitution

$Molarity = \frac{2.1}{1}$

Simplification and result

       Molarity = 2.1

Answer 2

Answer:

2.05 M

Explanation:

Molarity is defined as number of moles of solute in 1 L of solution.

Molarity = $\frac{Number\ of\ moles\ of\ solute}{Volume\ of\ solution\ in\ L}$

Here we have 120 g of NaCl in 1 liter of solution.

Molar mass of NaCl = 58.5 g

Number of moles of NaCl = $\frac{Given\ mass\ of\ solute}{Molar\ mass\ of\ solute}$ = $\frac{120}{58.5}=2.05\ moles$

Volume of solution = 1 L

Molarity = $\frac{Number\ of\ moles\ of\ solute}{Volume\ of\ solution\ in\ L}=\frac{2.05}{1}=2.05\ moles\ per\ litre$