J.R. S. answered 04/04/19
Ph.D. University Professor with 10+ years Tutoring Experience
Write the balanced equation:
2Na(s) + Br2(g) ===> 2NaBr(s)
Find the limiting reactant:
moles Na present = 57.5 g Na x 1 mol/22.99 g = 2.50 moles Na
moles Br2 present = 44.1 g Br2 x 1 mol/159.8 g = 0.276 moles Br2
Clearly, Br2 is limiting, even though it takes 2 moles Na for every 1 mole Br2, the Br2 will run out first.
Calculate theoretical yield:
0.276 moles Br2 x 2 moles NaBr/mol Br2 = 0.552 moles NaBr x 102.9 g/mol NaBr = 56.8 g NaBr
Calculate % yield = actual yield/theoretical yield (x100%) = 52.1 g/56.8 g (x100%) = 91.7 % yield