Question

Calculate the number of moles of solute in 73.97 mL of 0.1955 M K2Cr2O7(aq).

Answer 1

The number of mole of the solute is 0.0145 mol

Step-by-step explanation

Given that;

The volume of the solution is 73.97mL

The concentration of the solution is 0.1955M

Follow the steps below to find the number of moles of the solute

`\text{ Molarity = }\frac{\text{ number of moles}}{\text{ volume of solution}}`

Convert the volume of the solution to Liters

Recall, 1mL = 0.001L

`\begin{gathered} \text{ 1mL }\rightarrow\text{ 0.001L} \\ \text{ 73.97mL }\rightarrow\text{ xL} \\ \text{ cross multiply} \\ \text{ 1mL }*\text{ xL = 73.97mL }*\text{ 0.001L} \\ \text{ Isolate xL} \\ \text{ xL = }\frac{73.97\cancel{mL}*\text{ 0.001L}}{1\cancel{mL}} \\ \\ \text{ xL = 73.97 }*\text{ 0.001} \\ \text{ x = 0.07393L} \end{gathered}`
`\begin{gathered} \text{ 0.1955 = }\frac{\text{ number of moles}}{0.07393} \\ \text{ cross multiply} \\ \text{ number of moles = 0.0145 mol} \end{gathered}`

Therefore, the number of mole of the solute is 0.0145 mol