Question

Question 8 (2 points) Determine the molarity of a solution formed by dissolving 97.7 g LiBr in enough water to yield 750.0 mL of solution 0.768 M 0.130 M 1.18 M 1.50 M 2.30 M

Answer 1

Molar mass of LiBr,

MM = 1*MM(Li) + 1*MM(Br)

= 1*6.968 + 1*79.9

= 86.868 g/mol

mass(LiBr)= 97.7 g

use:

number of mol of LiBr,

n = mass of LiBr/molar mass of LiBr

=(97.7 g)/(86.87 g/mol)

= 1.125 mol

volume , V = 7.5*10^2 mL

= 0.75 L

use:

Molarity,

M = number of mol / volume in L

= 1.125/0.75

= 1.50 M

Answer: 1.50 M