M5 - excess reactant

[Emma Healy 2J]

For M5 in the textbook, why is BrF3 the excess reactant and not the limiting reactant?

[Sophia Hu 1A]

The problem gives you the balanced reaction and says that it requires 6 moles of ClO2 for 2 moles of BrF3. It then tells you that you have 6 moles of ClO2 and 5 moles of BrF3.

If you have 12 moles of ClO2 this means you only need 4 moles of BrF3. You can determined this from the equation because you have double the number of moles of ClO2 than it states in the reaction. Since you have 5 moles of BrF3, then BrF3 is in excess.

[Sofia Lucido 3L]

is the excess reactant because you have more moles of it than you need.

The problem says that you have 12 mol of and 5 mol of . You can use the mole ratio from the balanced equation to find out how many moles of you would need if you started with 12 moles of :



Moles of cancels and you are left with 4 moles of .

Since according to the balanced equation you only need 4 moles of but you have 5 moles, it is in excess.

Hope this helps!