Question

Calculate the number of grams of solute in 500.0 mL of 0.189 M KOH.

Answer 1

Answer : The number of grams of solute in 500.0 mL of 0.189 M KOH is, 5.292 grams

Solution : Given,

Volume of solution = 500 ml

Molarity of KOH solution = 0.189 M

Molar mass of KOH = 56 g/mole

Formula used :

$Molarity=\frac{\text{Mass of KOH}\times 1000}{\text{Molar mass of KOH}\times \text{Volume of solution in ml}}$

Now put all the given values in this formula, we get the mass of solute KOH.

$0.189M=\frac{\text{Mass of KOH}\times 1000}{(56g/mole)\times (500ml)}$

$\text{Mass of KOH}=5.292g$

Therefore, the number of grams of solute in 500.0 mL of 0.189 M KOH is, 5.292 grams

Answer 2

$\boxed{{\text{5}}{\text{.292 g}}}$ of KOH is present in 500 mL of 0.189 M KOH solution.

Further Explanation:

The concentration is the proportion of substance in the mixture. The most commonly used concentration terms are as follows:

1. Molarity  $\left(M\right)$

2. Molality  $\left(m\right)$

3. Mole fraction  $\left(X\right)$

4. Parts per million  $\left({{\text{ppm}}}\right)$

5. Mass percent  $\left({\left({{\text{w/w}}}\right)\%}\right)$

6. Volume percent  $\left({\left({{\text{v/v}}}\right)\%}\right)$

Molarity is a concentration term that is defined as the number of moles of solute dissolved in one litre of the solution. It is denoted by M and its unit is mol/L.

The formula to calculate the molarity of KOH is as follows:

${\text{Molarity of KOH solution}}=\frac{{{\text{amount}}\;\left({{\text{mol}}}\right)\;{\text{of}}\;{\text{KOH}}}}{{\;{\text{volume }}\left({\text{L}}\right)\;{\text{of}}\;{\text{solution}}}}$                         ......(1)

Rearrange equation (1) to calculate the amount of KOH.

${\text{Amount}}\;\left({{\text{mol}}}\right)\;{\text{of}}\;{\text{KOH}}=\left( {{\text{Molarity of KOH solution}}}\right)\left({\;{\text{Volume }}\left({\text{L}}\right)\;{\text{of KOH }}{\text{solution}}}\right)$    ......(2)

The molarity of the KOH solution is 0.189 M or 0.189 mol/L.

The volume of KOH solution is 500 mL.

Substitute these values in equation (2)

$\begin{aligned}{\text{Amount}}\;\left({{\text{mol}}}\right)\;{\text{of}}\;{\text{KOH}}&=\left({{\text{0}}{\text{.189 mol/L}}}\right)\left({500\;{\text{mL}}}\right)\left({\frac{{1\;{\text{L}}}}{{{{10}^{ - 3}}{\text{mL}}}}}\right)\\&=0.0945\;{\text{mol}}\\\end{aligned}$

The formula to calculate the mass of KOH is,

${\text{Mass of KOH}}=\left({{\text{Amount of KOH}}}\right)\left({{\text{Molar mass of KOH}}}\right)$     ......(3)

The amount of KOH is 0.0945 mol.

The molar mass of KOH is 56 g/mol.

Substitute these values in equation (3)

$\begin{aligned}{\text{Mass of KOH}}&=\left({{\text{0}}{\text{.0945 mol}}}\right)\left({\frac{{56\;{\text{g}}}}{{1\;{\text{mol}}}}}\right)\\&=5.292\;{\text{g}}\\\end{aligned}$

So the mass of KOH is 5.292 g.

Learn more:

1. What is the mass of 1 mole of viruses: brainly.com/question/8353774

2. Determine the moles of water produced: brainly.com/question/1405182

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Solutions

Keywords: KOH, molarity, 500 mL, 5.292 g, mol/L, 0.189 M, molar mass, 56 g/mol, concentration, concentration terms, volume.