Given:
70g C7H6O3
80g C4H6O3
Required:
Limiting reactant
Solution:
The balanced chemical reaction is C7H6O3 + C4H6O3 + 23/4O2 -> 11CO2 + 6H2O
Molar mass of C7H6O3 = 138 g/mol
Molar mass of C4H6O3 = 102 g/mol
70g C7H6O3 (1 mol C7H6O3/138g C7H6O3)(1 mol C4H6O3/ 1mol C7H6O3)(102g C4H6O3/1mol C4H6O3) = 51.74g C4H6O3
80g C4H6O3 - 51.74g C4H6O3 = 28.26g C4H6O3
There are 28.26g C4H6O3 left after reacting it with C7H6O3, therefore the limiting reactant is C7H6O3.