Question

Find the percent by mass of sodium chloride in a 1.20 M NaCl solution. The density of the solution is 1.06 g/mL

Answer 1

To calculate the percent by mass of NaCl in a 1.20 M NaCl solution with a density of 1.06 g/mL, you determine the mass of NaCl per liter using the molarity and molar mass of NaCl, find the mass of one liter of the solution via its density, and then divide and multiply by 100%. The result is a 6.61% NaCl composition by mass.

Step-by-step explanation:

The question asks for the percent by mass of sodium chloride (NaCl) in a 1.20 M NaCl solution with a density of 1.06 g/mL. The molarity of the NaCl solution (MNaCl) can help us calculate the percent by mass, applying the formula mass of NaCl and the solution's density.

To find the mass of NaCl in grams per liter, we can use the molarity of the solution and the molar mass of NaCl. The molar mass of NaCl is approximately 58.44 g/mol. Since molarity is moles of solute per liter of solution (mol/L), 1.20 M NaCl contains 1.20 moles of NaCl per liter, which is 1.20 moles × 58.44 g/mol = 70.128 g of NaCl per liter of solution.

Given the density of the solution, we can find the mass of 1 liter of solution by multiplying the density by 1000 mL/L, which gives 1.06 g/mL × 1000 mL = 1060 g. The percent by mass of NaCl is calculated by dividing the mass of NaCl by the mass of the solution and then multiplying by 100%. Therefore, the percent by mass is (70.128 g NaCl / 1060 g solution) × 100% = 6.61%.

Answer 2

Answer: The mass percent of sodium chloride in solution is 6.616 %

Step-by-step explanation:

Molarity is defined as the number of moles present in one liter of solution.

Mathematically,

`\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}`

We are given:

Molarity of NaCl solution = 1.20 M

This means that 1.20 moles of NaCl is present in 1 L or 1000 mL of solution

• To calculate the mass for given number of moles, we use the equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}`

Molar mass of NaCl = 58.44 g/mol

Moles of NaCl = 1.20 moles

Putting values in above equation, we get:

`1.20mol=\frac{\text{Mass of NaCl}}{58.44g/mol}\\\\\text{Mass of NaCl}=(1.20mol* 58.44g/mol)=70.13g`

• To calculate the mass of solution, we use the equation:

`\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}`

Density of solution = 1.06 g/mL

Volume of solution = 1000 mL

Putting values in above equation, we get:

`1.06g/mL=\frac{\text{Mass of solution}}{1000mL}\\\\\text{Mass of solution}=(1.06g/mL* 1000mL)=1060g`

• To calculate the mass percentage of sodium chloride in solution, we use the equation:

`\text{Mass percent of sodium chloride}=\frac{\text{Mass of sodium chloride}}{\text{Mass of solution}}* 100`

Mass of solution = 1060 g

Mass of sodium chloride = 70.13 g

Putting values in above equation, we get:

`\text{Mass percent of sodium chloride}=(70.13g)/(1060g)* 100=6.616\%`

Hence, the mass percent of sodium chloride in solution is 6.616 %