Using the equation N2+3H22NH3, how many grams of hydrogen must react if the reaction needs 127 grams of NH3?

3 Answers

22.6 g H2

Explanation:

3H2::2NH3

32H2::1NH3

Moles of NH3=12717.0

So moles of H2=3212717.0=11.2

Mass of H2=11.2 mol×2.016 g/mol=22.6 g

Jul 2, 2016

22.6 g of H2 must react.

Given: Mass of NH3 and the chemical equation.

Find: Mass of H2.

Strategy:

The central part of any stoichiometry problem is to convert moles of something to moles of something else.

(a) We start with the balanced chemical equation for the reaction.

(b) We can use the molar mass of NH3 to find the moles of NH3.

(c) We can use the molar ratio from the equation to convert moles of NH3 to moles of H2.

moles of NH3molar ratioXl−−−−−−moles of H2

(d) Then we can use the molar mass to convert the moles of H2 to mass of H2.

Our complete strategy is:

Mass of NH3molar massXl−−−−−−moles of NH3molar ratioXl−−−−−−moles of H2molar massXl−−−−−−mass of H2

Solution

(a) The balanced equation is

N2+3H22NH3

(b) Calculate moles of NH3

127g NH3×1 mol NH317.03g NH3=7.457 mol NH3

(c) Calculate moles of H2

The molar ratio of H2 to NH3 is 3 mol H22 mol NH3.

Moles of H2=7.457mol NH3×3 mol H22mol NH3=11.19 mol H2

(d) Calculate the mass of H2

11.19mol H2×2.016 g H21mol H2=22.6 g H2

**Answer: ** 22.6 g of H2 must react.

Jul 2, 2016

22.58gH2

Explanation:

N2+3H22NH3

If 127 grams of necessary we can use stoichiometry conversions to find the mass of Hydrogen required.

127gNH31molNH317.04gNH33molH22molNH32.02gH21molH2=

N=114.01g=14.01
H=31.01g=3.03

14.01+3.03=17.04g

127gNH31molNH317.04gNH33molH22molNH32.02gH21molH2=

=22.58gH2