Question

Given that the molar mass of NaCl is 58.44 g/mol, what is the molarity of a solution that contains 87.75 g of NaCl in 500. mL of solution?
Use Molarity equals StartFraction moles of solute over liters of solution EndFraction..
0.333 M
0.751 M
1.50 M
3.00 M

Answer 1

To find the molarity (M) of a solution, we can use the formula:

\[
M = \frac{\text{moles of solute}}{\text{liters of solution}}
\]

### Step 1: Calculate the moles of NaCl

First, we need to convert the mass of NaCl into moles. We use the molar mass given:

\[
\text{molar mass of NaCl} = 58.44 \, \text{g/mol}
\]

Now, calculate the moles of NaCl:

\[
\text{moles of NaCl} = \frac{\text{mass}}{\text{molar mass}} = \frac{87.75 \, \text{g}}{58.44 \, \text{g/mol}} \approx 1.501 \, \text{mol}
\]

### Step 2: Convert volume from mL to L

Next, we convert the volume of the solution from milliliters (mL) to liters (L):

\[
500 \, \text{mL} = 0.500 \, \text{L}
\]

### Step 3: Calculate the molarity

Now we can substitute the values into the molarity formula:

\[
M = \frac{\text{moles of NaCl}}{\text{liters of solution}} = \frac{1.501 \, \text{mol}}{0.500 \, \text{L}} \approx 3.002 \, \text{M}
\]

Therefore, rounding to three significant figures, the molarity of the solution is approximately:

\[
\boxed{3.00 \, \text{M}}
\]