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Your question specified 2 moles of nitrogen. I would be quite justified in assuming that the questioner meant 2 moles of dinitrogen gas, i.e. the equivalent of 4 moles of NITROGEN atoms. Thus, if 2 moles of dinitrogen gas are specified, 6 moles of dihydrogen gas are required.

In this case, the mole ratio of PCl₃ to PCl₅ is 1 : 1.

Mole ratios allow comparison of the amounts of any two materials in a balanced equation. Calculations can be made to predict how much product can be obtained from a given number of moles of reactant.

Divide the number of grams of each reactant by the number of grams per mole for that reactant. 50.0 g of Na are used in this reaction, and there are 22.990 g/mol. 50.0 ÷ 22.990 = 2.1749. 2.1749 moles of Na are used in this reaction.

The stoichiometric coefficients can be thought of as representing the number of moles of a species participating in a chemical reaction per mole of reaction. One mole of reaction (molrxn) refers to a reaction unit. In order to define a mole of reaction the chemical equation must be known.

Big, because atoms and molecules are way too small to count, so we mass large numbers of them instead, and use molar mass to convert to the NUMBER of moles of them. This number is then used in a ratio conversion based on the mole ratios in the balanced chemical equation.

A substance’s molar mass is calculated by multiplying its relative atomic mass by the molar mass constant (1 g/mol). The molar mass constant can be used to convert mass to moles. By multiplying a given mass by the molar mass, the amount of moles of the substance can be calculated.