Question

How many grams of KBr are required to make 550. mL of a 0.115 M KBr solution?

~Also please explain how you got the answer.

Answer 1

Answer: 7.53 g KBr

Step-by-step explanation:

0.115 M = n mol KBr / .55 L solution

n = 0.06325 mol KBr

mass = 0.06325 mol KBr (119 g / mol) = 7.53 g KBr

Answer 2

Molarity is expressed as the number of moles of solute per volume of the solution. For example, we are given a solution of 2M NaOH this describes a solution that has 2 moles of NaOH per 1 L volume of the solution. We calculate as follows:

0.115 M = n mol KBr / .55 L solution

n = 0.06325 mol KBr

mass = 0.06325 mol KBr (119 g / mol) = 7.53 g KBr