Question

Barium oxalate is used as a colorant to produce the green color in fireworks. Imagine that you have been assigned to prepare barium oxalate by reacting barium hydroxide octahydrate (Ba(OH)2·8H2O) with oxalic acid dihydrate (H2C2O4·2H2O). Find the number of grams of oxalic acid dihydrate that would be required to completely react with 5.3 g of barium hydroxide octahydrate. Use correct significant figures. Do not include a unit with your answer or it will be counted wrong.

H2C2O4·2H2O	126.07 g/mol
H2C2O4	90.03 g/mol
Ba(OH)2·8H2O	315.46 g/mol
Ba(OH)2	171.34 g/mol

Answer 1

Answer – We are given, mass of Ba(OH)₂·8H₂O = 5.3 g

Reaction - Ba(OH)₂·8H₂O + H₂C₂O₄·2H₂O ----> BaC₂O₄ + 12 H₂O

Now we need to calculate the moles of Ba(OH)₂·8H₂O

Moles of Ba(OH)₂·8H₂O = 5.3 g / 315.46 g.mol^-1

                                          = 0.0168 moles

From the balanced reaction

1 mole of Ba(OH)₂·8H₂O = 1 moles of H₂C₂O₄·2H₂O

So, 0.0168 moles of Ba(OH)₂·8H₂O = ?

= 0.0168 moles of H₂C₂O₄·2H₂O

Mass of H₂C₂O₄·2H₂O = 0.0168 moles * 126.07 g/mol

                                      = 2.1 g

2.1 grams of oxalic acid dihydrate that would be required to completely react with 5.3 g of barium hydroxide octahydrate