Question

how many moles of barium hydroxide, Ba(OH2), would be required to react with 117 g hydrogen bromide, HBr?

Answer 1

The moles of Ba(OH)2 that is required to react with 117 HBr is calculated as below

find the moles of HBr used
mass/ molar mass = 117 g/ 80.9 g/mol = 1.446 moles

write the reacting equation

Ba(OH)2 + 2 HBr = BaBr2 + 2 H2O

by use of mole ratio of Ba(OH)2 : HBr which is 1:2 the moles of Ba(OH)2 is therefore
= 1.446 moles x1/2 = 0.723 moles of Ba(OH)2