If 12 mol of lithium were reacted with excess nitrogen gas, how many moles of lithium nitride would be produced?

4 moles

Explanation:

From the balanced chemical equation, it can be seen that 6 moles of lithium react with 1 mole of nitrogen to give 2 moles of lithium nitride.

Now as nitrogen is in excess, lithium is the limiting reagent as it limits the formation of products.

As 6 moles of lithium produce 2 moles of lithium nitride.

12 moles of lithium will produce= of lithium nitride.

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.