Question

A) The lab tech called in sick today and you are called in to help prepare

750.0 mLs of 2.00 M K3PO4 (212.27 g/mol) solution. What mass of K3PO4
should you weigh out?

Answer 1

318.405 g

Step-by-step explanation:

We are given;

• Volume of K₃PO₄ solution to be prepared as 750.0 mL or 0.75 L
• Molarity of the solution to be prepared as 2.00 M

We are required to determine the mass of K₃PO₄ to be measured.

Step 1: Determine the number of moles of K₃PO₄

Molarity = Moles ÷ Volume

Rearranging the formula;

Number of moles = Molarity × Volume

Therefore;

Moles of K₃PO₄ = 2.00 M × 0.75 L

= 1.5 moles

Step 2: Determine the mass of K₃PO₄ to be measured

Mass = Number of moles × Molar mass

Molar mass of K₃PO₄ = 212.27 g/mol

Therefore;

Mass of K₃PO₄ = 1.5 moles × 212.27 g/mol

= 318.405 g

Therefore, the mass of K₃PO₄ that should be weighed is 318.405 g