Question

What will be the mass percent of NaOH in a solution prepared by adding 5g of NaOH in 15g of water.

Answer 1

Mass of NaOH(solute) = 5g

Mass of water(solvent) = 15g

Mass of solution = 5 + 15 = 20g

Mass percent = (mass of solute/mass of solution) × 100 = (5/20) × 100 = 25%

Answer 2

The mass percent of NaOH is 25%.

Given - Mass of solute and solvent

Find - Mass percentage

Solution - The mass percentage can be calculated by the formula -

Mass percentage = mass of solute/mass of solution*100

Mass of solute = 5 grams

Mass of solution = mass of solute + mass of solvent

Mass of solution = 5 + 15

Mass of solution = 20 grams

Keep the values in formula to find the mass percentage.

Mass percentage = $\frac{5}{20} \times 100$

Cancelling zero that is common in numerator and denominator.

Mass percentage = 5 × 5

Performing multiplication to find the mass percentage

Mass percentage = 25%

Hence, the mass percentage of NaOH is 25%.

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