Question

BRAINLIEST
Kristen dissolves 49.24 grams of NaOH in enough water to make 195 mL of solution. What is the molarity of Kristen's solution? Round your answer to two digits after the decimal point.

Answer 1

Answer:

The correct answer is 6.31 M

Explanation:

The molecular weight (MM) of NaOH is calculated as follows:

MM(NaOH) = Molar mass Na + Molar mass O + Molar mass H

                   = 23 g/mol + 16 g/mol + 1 g/mol

                   = 40 g/mol

We need the MM to convert from grams to moles. The molarity (moles of solute per liter of solution, in mol/L) can be calculated by dividing the mass into the volume in liters (195 ml = 0.195 L) and then multiplying by the MM as follows:

M = 49.24 g/0.195 L x 1 mol/40 g = 6.31 mol/L = 6.31 M

Answer 2

Answer:

M = 6.31 M

Explanation:

Data:

mass = 49.24 g of NaOH

solution volume = 195 mL = 0.195 L

MW NaOH = 39.99 g/mol

M = ?

The equation to calculate the molarity of a solution is as follows:

$M=\frac{moles}{solution volume}$

To calculate the moles of NaOH the following equation is used:

$MW=\frac{mass}{mol}$

Where MW is the molecular weight of NaOH, now we must clear the moles from the previous equation.

$mol=\frac{mass}{MW}$

$mol=\frac{49.24g}{39.99\frac{g}{mol} }=1.23 mol$

We place the moles and the volume of the solution in the molarity equation

$M=\frac{1.23mol}{0.195L} =6.31 M$