Let’s go step by step to solve this problem.
We are given the balanced chemical equation:
N₂(g) + 3H₂(g) → 2NH₃(g)
This tells us that for every
1 molecule of N₂, we need
3 molecules of H₂ to make
2 molecules of NH₃.
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Part 1a: What are the coefficients?
Coefficients are the numbers in front of each substance in the balanced equation.
- For
N₂: there is no number written, which means it’s
1
- For
H₂: the number is
3
- For
NH₃: the number is
2
✔ So:
- N₂ =
1
- H₂ =
3
- NH₃ =
2
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Part 1b: Draw particle models
We don’t need to draw here, but just to understand:
- N₂ is shown as two circles stuck together (diatomic molecule)
- H₂ is also two small circles stuck together — and we need 3 of them
- NH₃ is one big circle (N) with three small ones (H) around it — and we get 2 of those
The drawing in the image shows:
- One N₂ (two red circles)
- Three H₂ (three pairs of small circles)
- Two NH₃ (each with one big circle and three small ones)
That matches the ratio 1:3:2.
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Part 2a & 2b: Calculate amounts and reduce ratios
We’re told to calculate how many molecules are consumed or produced if the reaction happens:
#### Case 1: Single reaction (happens once)
From the equation:
- N₂ consumed =
1
- H₂ consumed =
3
- NH₃ produced =
2
Ratio N₂ : H₂ : NH₃ =
1 : 3 : 2 → already reduced!
#### Case 2: Reaction occurs 100 times
Multiply each coefficient by 100:
- N₂ = 1 × 100 =
100
- H₂ = 3 × 100 =
300
- NH₃ = 2 × 100 =
200
Ratio = 100 : 300 : 200 → divide all by 100 →
1 : 3 : 2
#### Case 3: Reaction occurs 538 times
Multiply each coefficient by 538:
- N₂ = 1 × 538 =
538
- H₂ = 3 × 538 = let’s calculate:
3 × 500 = 1500
3 × 38 = 114
Total = 1500 + 114 =
1614
- NH₃ = 2 × 538 =
2 × 500 = 1000
2 × 38 = 76
Total = 1000 + 76 =
1076
Ratio = 538 : 1614 : 1076 → divide all by 538 →
1 : 3 : 2
✔ All ratios reduce to 1:3:2 because they’re based on the same balanced equation.
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Final Answer:
For part 1a:
N₂ = 1, H₂ = 3, NH₃ = 2
For part 2 table:
| Situation | N₂ Consumed | H₂ Consumed | NH₃ Produced | Ratio N₂:H₂:NH₃ (reduced) |
|-----------|-------------|-------------|--------------|---------------------------|
| Single reaction | 1 | 3 | 2 | 1:3:2 |
| 100 times | 100 | 300 | 200 | 1:3:2 |
| 538 times | 538 | 1614 | 1076 | 1:3:2 |
Parent Tip: Review the logic above to help your child master the concept of molar ratio worksheet answers.