If you have 3.5 mol of n2, and 1.75 mol of h2, how many moles of n2 are there in excess? reaction: n2 + 3 h2 → 2 nh3

2.917 moles of are present in excess.

Explanation: For the given reaction:

Number of moles of = 3.5 moles

Number of moles of = 1.75 moles

Here, the is considered as limiting reagent as it limits the amount of product formed.

By stoichiometry, 3 mole of require 1 mole of to produce 2 moles of .

So, 1.75 moles of will require =

Moles of reacted with = 0.583 moles

                                  = 2.917 moles

the volume of fluid displaced would equal the volume of the gas. use a gas syringe - this is a laboratory instrument that can be used to withdraw a certain volume of gas from a closed system or to measure the volume of gas from a chemical reaction.