To convert from a given quantity of one reactant or product tothe quantity of another reactant or product: First, convert thegiven quantity to moles. Use molar masses to convert masses tomoles, and use Avogadro's number (6.02×1023 particles per mole) toconvert number of particles to moles. Next, convert moles of thegiven reactant or product to moles of the desired reactant orproduct using the coefficients of the balanced chemical equation.For example, in the chemical equation 2H2+O2→2H2O the coefficientstell us that 2 mol of H2 reacts with 1 mol of O2 to produce 2 molof H2O. Finally, convert moles of the desired reactant or productback to the desired units. Again, use molar masses to convert frommoles to masses, and use Avogadro's number to convert from moles tonumber of particles.

Hydrogen gas, H2, reacts with nitrogen gas, N2, to form ammoniagas, NH3, according to the equation 3H2(g)+N2(g)→2NH3(g)

NOTE: Throughout this tutorial use molar masses expressed tofive significant figures.

Part A: How many moles of NH3 can be produced from 21.0 mol ofH2 and excess N2?

Part B: How many grams of NH3 can be produced from 4.99 mol ofN2 and excess H2.

Part C: How many grams of H2 are needed to produce 12.43 g ofNH3?

Part D: How many molecules (not moles) of NH3 are produced from4.35×10−4 g of H2?