We're doing stoichiometry and my teacher isn't the best at explaining things. I've taken notes and tried getting help and she never really helps me, and I tried from a few of my peers but none of them understood it either. I have this packet and don't understand the slightest bit how to do it.
The first problem.
1. Considering the reaction represented by the (unbalanced) equation
N2(g) + H2(g) ---> NH3(g)
determine the number of moles of NH3(g) that can be produced from the following:
a. 0.20 mol N2(g) reacts completely with H2(g).
b. 0.30 mol H2(g) reacts differently with N2(g).
The first problem.
1. Considering the reaction represented by the (unbalanced) equation
N2(g) + H2(g) ---> NH3(g)
determine the number of moles of NH3(g) that can be produced from the following:
a. 0.20 mol N2(g) reacts completely with H2(g).
b. 0.30 mol H2(g) reacts differently with N2(g).
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N2(g) + 3 H2(g) → 2 NH3(g)
a. (0.20 mol N2) x (2 mol NH3 / 1 mol N2) = 0.40 mol NH3
b. (0.30 mol H2) x (2 mol NH3 / 3 mol H2) = 0.10 mol NH3
a. (0.20 mol N2) x (2 mol NH3 / 1 mol N2) = 0.40 mol NH3
b. (0.30 mol H2) x (2 mol NH3 / 3 mol H2) = 0.10 mol NH3
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You have to look at the coefficient ratios in the balanced chemical equation.
So first, you must balance the eq.
Nitrogen is the minor component in the product; there is only one 'N', there are three 'H' atoms,
So lets assume that we have just one molecule of N2 reactant...
One molecule of N2 will make two molecules of NH3, so how many H atoms are needed?
the answer is 2 x 3 = 6 H atoms (bcoz two NH3 molecules contain six H's)
To provide six hydrogen atoms, we need three H2 molecules.
The balanced eq is:
N2 + 3 H2 <--> 2 NH3
a. The N2:NH3 ratio is 1:2, so if you start with 0.20 mol N2, you get 0.20 x (2/1) = 0.40 mol NH3
b. The H2:NH3 ratio is 3:2. starting with 0.3 mol H2 gives 0.3 x (2/3) = 0.20 mol NH3.
Actually, these are maximum amounts, and this yield is never attained since as NH3 concentrtation increases, NH3 decomposes to form N2 and H2 gas again. Next year in chemistry, you study equilibrium, and find out more about this.
So first, you must balance the eq.
Nitrogen is the minor component in the product; there is only one 'N', there are three 'H' atoms,
So lets assume that we have just one molecule of N2 reactant...
One molecule of N2 will make two molecules of NH3, so how many H atoms are needed?
the answer is 2 x 3 = 6 H atoms (bcoz two NH3 molecules contain six H's)
To provide six hydrogen atoms, we need three H2 molecules.
The balanced eq is:
N2 + 3 H2 <--> 2 NH3
a. The N2:NH3 ratio is 1:2, so if you start with 0.20 mol N2, you get 0.20 x (2/1) = 0.40 mol NH3
b. The H2:NH3 ratio is 3:2. starting with 0.3 mol H2 gives 0.3 x (2/3) = 0.20 mol NH3.
Actually, these are maximum amounts, and this yield is never attained since as NH3 concentrtation increases, NH3 decomposes to form N2 and H2 gas again. Next year in chemistry, you study equilibrium, and find out more about this.