how do I calculate how many moles of NO2 form when each quantity of reactant complty reacts?

Answer 1

Assuming that the reaction takes place near room temperature, which is close to nitrogen dioxide's boiling point (21.2 C): the mass of NO₂ produced cannot be measured, and you cannot use molar mass. Therefore, you would need to go by the mole:mole ratio in the balanced equation. Let's set up a generic reaction equation like this:

___A + ___B → ___NO₂ (g) + ___C

1. Suppose the balanced equation is __2_A + __1__B → _3__NO₂ (g) + _1__C. This means that the ratios are 2 moles of compound A: 3 moles of NO₂, and 1 mole of Compound B: 3 moles of NO₂.
2. Find the # moles of either A or B that were reacted. (Choosing B might be easier, since you can just triple it by 3 to get # moles NO₂ produced.)
3. If B is a pure compound, then its mass reacted should be known, and you would divide that by its molar mass (g/mole) to get the # moles.
4. If B is in a solution, then its concentrated in % mass, molarity or molality should be known, and you would multiply by the total mass or volume of the solution used to get the # moles of B.

Hope this helps.