To determine the limiting reactant, we need to analyze the reaction and the mole ratio between $\text{H}_2$ and $\text{O}_2$.

Reaction:

The chemical reaction between hydrogen gas ($\text{H}_2$) and oxygen gas ($\text{O}_2$) to form water ($\text{H}_2\text{O}$) is: $2 \text{H}_2 + \text{O}_2 \rightarrow 2 \text{H}_2\text{O}$

Step-by-Step Solution:

1. Mole Ratio: According to the balanced equation, 2 moles of $\text{H}_2$ react with 1 mole of $\text{O}_2$.

2. Given Quantities:

   • $\text{H}_2$: 3.0 moles
   • $\text{O}_2$: 7.0 moles

3. Determine Limiting Reactant:

   • For 3.0 moles of $\text{H}_2$: $\text{Required } \text{O}_2 = \frac{3.0 \, \text{moles } \text{H}_2}{2} = 1.5 \, \text{moles } \text{O}_2$
   • Since we have 7.0 moles of $\text{O}_2$, which is more than enough to react with the 3.0 moles of $\text{H}_2$, $\text{H}_2$ is the limiting reactant.

Answer:

The limiting reactant is $\text{H}_2$.

Would you like a more detailed explanation of any part?

Here are some related questions to consider:

1. What is the excess reactant in this reaction, and how much is left over?
2. How many moles of $\text{H}_2\text{O}$ would be produced in this reaction?
3. If you started with 5 moles of $\text{H}_2$ and 7 moles of $\text{O}_2$, what would be the limiting reactant?
4. How does the concept of a limiting reactant apply in industrial chemical processes?
5. How would the reaction differ if it was taking place under non-ideal conditions, such as in a closed container with limited space?

Tip: Always compare the mole ratio of reactants based on the balanced equation to find the limiting reactant accurately.