a) The correct balancing of this reaction is:
BaBr2 + Na2SO4 -> BaSO4 + 2NaBr
Which is letter C
b) 0.625 grams of Na2SO4, we need to find the number of moles of Na2SO4 in the reaction, to do that we will need the molar mass, which is 142.04g/mol, therefore
142.04 g = 1 mol
0.625 g = x moles
x = 0.0044 moles of Na2SO4 in the reaction
In order to react, we need 1 Na2SO4 and 1 BaBr2, we know that by checking our balanced equation, so if we have a 1:1 ratio in the equation, if we have 0.0044 moles of Na2SO4, we will also need 0.0044 moles of BaBr2
Now to find the mass of BaBr2, we will also use its molar mass, which is 297.14g/mol
297.14 g = 1 mol
x grams = 0.0044 moles
x = 1.31 grams of BaBr2
Option D
