Question

Kristen dissolves 32.02 grams of NaOH in enough water to make 186 mL of solution. What is the molarity of Kristen's solution? Round your answer to two digits after the decimal point.

Answer 1

Molarity = 4.31 M

Step-by-step explanation:

Data:

mass NaOH = 32.02 g

solution volume = 186 mL = 0.186 L

MW NaOH = 39.99 g/mol

The equation for calculating molarity is as follows:

`M=(solute moles)/(solution volume)`

To calculate the moles of NaOH we use the following equation:

`MW=(mass)/(moles)`

Where MW is the molecular weight of the solute.

We clear the moles of the previous equation:

`moles=(mass)/(MW)`

Where the molecular weight of NaOH is 39.99 g/mol.

`moles=(32.02g)/(39.99(g)/(mol) )=0.801mol`

We substitute the values ​​of moles and volume in the molarity equation.

`M=(0.801mol)/(0.186L)=4.31M`

Answer 2

The molarity of the solution is = 4.31 M

Step-by-step explanation:

To find the molarity within a solution, the equation is used:

• M = Moles of solute / Liters of solution

- The first thing we have to do is convert the grams of NaOH to moles. And the mL of solution in liters of solution.

• 32.02g of NaOH ÷ 39.997 g / mol = 0.801 mol NaOH

• 186 mL of solution = 0.186L of solution

- Now with the data the molarity equation is solved:

• M = 0.801 ÷ 0.186

• M = 4.306

- Approaching would give that:

• M = 4.31