Question

Which would produce a greater number of moles of product: a given amount of hydrogen gas reacting with an excess of oxygen gas to produce water, or the same amount of hydrogen gas reacting with an excess of nitrogen gas to make ammonia? Support your answer.

Short answer

A given amount of hydrogen gas reacting with an excess of oxygen gas to produce water will produce a greater number of moles of product than the same amount of hydrogen gas reacting with an excess of nitrogen gas to make ammonia. This is because the mole ratio of product to reactant in the water-producing reaction (H2O: H2) is 1, which is greater than the mole ratio in the ammonia-producing reaction (NH3: H2), which is \(\frac{2}{3}\).

Step-by-step solution

Write the balanced chemical equations for both reactions

First, we need to write the balanced chemical equations for both the reactions: 1. Hydrogen gas (H2) reacting with oxygen gas (O2) to produce water (H2O): \[2H_2 + O_2 \rightarrow 2H_2O\] 2. Hydrogen gas (H2) reacting with nitrogen gas (N2) to produce ammonia (NH3): \[3H_2 + N_2 \rightarrow 2NH_3\]

Calculate mole ratios for each reaction

Now, let's determine the mole ratios of product to reactant for each reaction using the balanced chemical equations. For reaction 1: The mole ratio of water (H2O) to hydrogen (H2) is \[\frac{2 \text{ moles of } H_2O}{2 \text{ moles of } H_2} = 1\] For reaction 2: The mole ratio of ammonia (NH3) to hydrogen (H2) is \[\frac{2 \text{ moles of } NH_3}{3 \text{ moles of } H_2} = \frac{2}{3}\]

Compare the mole ratios

Now, we need to compare the mole ratios to determine which reaction would produce a greater number of moles of the product. Reaction 1: Mole ratio (H2O: H2) = 1 Reaction 2: Mole ratio (NH3: H2) = 2/3 Since the mole ratio in reaction 1 (H2O: H2) is greater than the mole ratio in reaction 2 (NH3: H2), reaction 1 will produce a greater number of moles of product (water) for the same amount of hydrogen gas reacting with an excess of oxygen gas.

Conclusion

A given amount of hydrogen gas reacting with an excess of oxygen gas to produce water will produce a greater number of moles of product than the same amount of hydrogen gas reacting with an excess of nitrogen gas to make ammonia. This is because the mole ratio of product to reactant in the water-producing reaction is greater than the mole ratio in the ammonia-producing reaction.

Key concepts

Chemical Reactions

Chemical reactions involve the transformation of reactants into products. When substances interact, they form new compounds or molecules. In chemical equations, reactants are written on the left, while products are on the right. For example, when hydrogen gas reacts with oxygen gas, water is formed. Similarly, hydrogen can react with nitrogen to form ammonia. Understanding the nature of these reactions helps predict the products formed and how the reactants behave when combined.
Reactants are substances present at the start of a reaction, and products are what you've got at the end. This establishes how substances change under certain conditions. By studying specific reactions, like the formation of water or ammonia in our case, you can gain insights into stoichiometry and predict chemical outcomes.

Mole Ratio

Mole ratio is a key concept in stoichiometry that explains the relationship between reactants and products in a balanced chemical equation. It tells us how many moles of one substance react or are produced by a certain number of moles of another.
In our example, the reaction between hydrogen and oxygen to form water has a 1:1 mole ratio between hydrogen and water. This means if you start with 2 moles of hydrogen, you'll end up with 2 moles of water. Contrast this with the hydrogen-nitrogen reaction to form ammonia, which has a 2:3 mole ratio. Here, 3 moles of hydrogen are required to produce 2 moles of ammonia. Understanding mole ratios helps determine the efficiency and quantity of product from given reactants.

Balanced Equations

Balanced equations are essential for accurately describing chemical reactions. They ensure that the number of atoms for each element is the same on the reactant side as on the product side, aligning with the law of conservation of mass.
For example, the balanced equation for hydrogen reacting with oxygen to form water is \[2H_2 + O_2 \rightarrow 2H_2O\]. Here, two molecules of hydrogen (totaling four hydrogen atoms) react with one molecule of oxygen (two oxygen atoms) to produce two water molecules. For the hydrogen and nitrogen reaction, the balanced equation is \[3H_2 + N_2 \rightarrow 2NH_3\]. This stipulates that three molecules of hydrogen react with one nitrogen molecule to produce two molecules of ammonia.
Balanced equations give a clear picture of how much reactant is needed and how much product will be formed, which is critical in stoichiometry.

Hydrogen Gas Reactions

Hydrogen gas is a reactive molecule and participates in various chemical reactions. In our context, we examined hydrogen's role in forming both water and ammonia.
When hydrogen reacts with oxygen, we get water. This reaction is quite familiar, fundamental, and showcases hydrogen's combustive properties. The equation \[2H_2 + O_2 \rightarrow 2H_2O\] reflects this. When hydrogen reacts with nitrogen, ammonia is produced, a process widely used in industrial fertilizers. The equation for this is \[3H_2 + N_2 \rightarrow 2NH_3\].
Hydrogen gas reactions are pivotal in industrial applications. Understanding these reactions is crucial for manipulating chemical processes efficiently. Whether in the context of energy sources or producing essential chemicals, hydrogen's reactivity plays a significant role in chemistry.