Question

A chemistry teacher needs to make 2.30 L of a potassium chloride solution for an experiment. The concentration of the required solution is 3.10 M. How many grams of KCl will she need to use?

a) 7.13 g KCl
b) 23.1 g KCl
c) 532 g KCl
d) 95.6 g KCl

Answer 1

To make a 2.30 L solution with a concentration of 3.10 M of KCl, the chemistry teacher will need to use 532 g of KCl.

Step-by-step explanation:

To calculate the mass of KCl needed to make a 2.30 L solution with a concentration of 3.10 M, we need to use the formula:

Molarity (M) = moles of solute (mol) / volume of solution (L)

Rearranging the formula, we have:

moles of solute (mol) = Molarity (M) x volume of solution (L)

Substituting the given values, we have:

moles of solute (mol) = 3.10 M x 2.30 L = 7.13 mol KCl

To calculate the mass, we can use the formula:

moles of solute (mol) = mass of solute (g) / molar mass (g/mol)

Rearranging the formula, we have:

mass of solute (g) = moles of solute (mol) x molar mass (g/mol)

The molar mass of KCl is 74.55 g/mol, so we have:

mass of solute (g) = 7.13 mol x 74.55 g/mol = 532.6 g KCl

Therefore, the correct answer is c) 532 g KCl.