How many grams of LiBr are in 125 mL of a 1.3 M solution

Question

Need help on a homework question

Answer 1

A 1.3 M solution means 1.3 mol/liter and 125 mL = 0.125 liters so the number of moles is:

(1.3 mol/L)(0.125 L) = 0.1625 moles

Calculate the molar mass of LiBr

Li = 6.941 x 1 = 6.941 g/mol

Br = 79.904 x 1 = 79.904 g/mol

------------------------------------------

86.845 g/mol

Calculate the mass of LiBr:

(0.1625 moles)(86.845 g/mol) = 14.11 grams

It would be appropriate to round to 2 sig figs so mass = 14 grams