Oxygen and hydrogen combine with a lot of heat or a spark, which provides sufficient activation energy, to produce water.

[tex]\[ O_2(g) + 2H_2(g) \longrightarrow 2H_2O(l) \][/tex]

Assume [tex]\(0.280 \text{ mol } O_2\)[/tex] and [tex]\(0.871 \text{ mol } H_2\)[/tex] are present initially.

After the reaction is complete:

1. How many moles of water are produced?
[tex]\[ H_2O: \square \text{ mol} \][/tex]

2. How many moles of hydrogen remain?
[tex]\[ H_2: \square \][/tex]

3. How many moles of oxygen remain?
[tex]\[ O_2: \square \][/tex]



Answer :

To solve the problem of determining the amount of moles of products and remaining reactants after a chemical reaction, we will follow these steps:

1. Identify the Initial Quantities:
- Initially, we have 0.280 mol of [tex]\( O_2 \)[/tex].
- Initially, we have 0.871 mol of [tex]\( H_2 \)[/tex].

2. Determine the Limiting Reactant:
- The balanced chemical equation is:
[tex]\[ O_2(g) + 2 H_2(g) \longrightarrow 2 H_2O(l) \][/tex]
- According to the equation, 1 mole of [tex]\( O_2 \)[/tex] reacts with 2 moles of [tex]\( H_2 \)[/tex]. Therefore, to fully react 0.280 mol of [tex]\( O_2 \)[/tex], we need:
[tex]\[ 0.280 \text{ mol } O_2 \times 2 = 0.560 \text{ mol } H_2 \][/tex]
- We compare this with the available [tex]\( H_2 \)[/tex]:
[tex]\[ 0.871 \text{ mol } H_2 \geq 0.560 \text{ mol } H_2 \][/tex]
- Since we have enough [tex]\( H_2 \)[/tex], [tex]\( O_2 \)[/tex] is the limiting reactant.

3. Calculate the Amount of Each Substance After the Reaction:
- All 0.280 mol of [tex]\( O_2 \)[/tex] will be consumed. Therefore:
[tex]\[ \text{Moles of } O_2 \text{ used} = 0.280 \text{ mol} \][/tex]
- Accordingly, the amount of [tex]\( H_2 \)[/tex] used is:
[tex]\[ \text{Moles of } H_2 \text{ used} = 0.280 \text{ mol} \times 2 = 0.560 \text{ mol} \][/tex]
- The remaining [tex]\( H_2 \)[/tex] is:
[tex]\[ 0.871 \text{ mol} - 0.560 \text{ mol} = 0.311 \text{ mol} \][/tex]
- The moles of [tex]\( H_2O \)[/tex] produced are:
[tex]\[ 2 \times 0.280 \text{ mol} = 0.560 \text{ mol} \][/tex]

4. Summarize the Results:
- Moles of water ([tex]\( H_2O \)[/tex]) produced: 0.560 mol
- Moles of remaining hydrogen ([tex]\( H_2 \)[/tex]): 0.311 mol
- Moles of remaining oxygen ([tex]\( O_2 \)[/tex]): 0.000 mol

Therefore:
[tex]\[ H_2 O : 0.560 \text{ mol} \][/tex]
[tex]\[ H_2 : 0.311 \text{ mol} \][/tex]
[tex]\[ O_2 : 0.000 \text{ mol} \][/tex]