Problem 10 - Chemistry Matter and Change

Question

Model Write the mole ratios for the reaction of hydrogen gas and oxygen gas, \(2 \mathrm{H}_{2}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \rightarrow 2 \mathrm{H}_{2} 0\) . Make a sketch of six hydrogen molecules reacting with the correct number of oxygen molecules. Show the water molecules produced.

Step-by-Step Solution

Answer

The mole ratios for the reaction are 2 moles of H2(g) reacting with 1 mole of O2(g) to produce 2 moles of H2O. For six hydrogen molecules reacting, 3 oxygen molecules are required, and 6 water molecules are produced. The sketch should show 6 hydrogen molecules and 3 oxygen molecules on the reactant side, and 6 water molecules on the product side.

Step 1: Identify the balanced chemical equation

In this exercise, the balanced chemical equation provided is: \[2 \mathrm{H}_{2}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \rightarrow 2 \mathrm{H}_{2} \mathrm{O}\]

Step 2: Determine the mole ratio

The balanced chemical equation tells us the mole ratio of the reactants and products. In this case, we have: - 2 moles of hydrogen gas (H2) react with - 1 mole of oxygen gas (O2) to produce - 2 moles of water molecules (H2O)

Step 3: Calculate the number of oxygen molecules reacting with six hydrogen molecules

Since the balanced chemical equation indicates that 2 moles of hydrogen molecules react with 1 mole of oxygen molecules, we have to determine the number of oxygen molecules reacting with six hydrogen molecules. Using the mole ratio, 6 hydrogen molecules will react with: \(6 \times \frac{1}{2} = 3\) oxygen molecules

Step 4: Calculate the number of water molecules produced

From the balanced chemical equation, we know that 2 moles of H2O are produced for every 2 moles of H2 reacting. So for 6 hydrogen molecules reacting: Number of water molecules produced = \(6 \times \frac{2}{2}\) Thus, 6 water molecules are produced.

Step 5: Make a sketch of the molecules reacting

Sketch the reaction as follows: 1. Draw 6 hydrogen molecules (H2) on the reactant side as 6 pairs of H atoms bonded together. 2. Draw 3 oxygen molecules (O2) on the reactant side as 3 pairs of O atoms bonded together. 3. Draw an arrow depicting the reaction direction. 4. Draw 6 water molecules (H2O) on the product side as 6 H2O molecules, each with two H atoms bonded to one O atom. The sketch should clearly show 6 hydrogen molecules and 3 oxygen molecules on the reactants side, and 6 water molecules on the products side.

Key Concepts

Balanced Chemical Equation

Chemical reactions are represented by balanced chemical equations. These equations show the reactants and the products formed from a chemical reaction. A balanced equation ensures that the number of atoms for each element is the same on both sides of the equation. This follows the Law of Conservation of Mass, which states that matter cannot be created or destroyed in a chemical reaction.

In the given reaction, the balanced chemical equation is:

• \[2 \mathrm{H}_{2} (\mathrm{g}) + \mathrm{O}_{2} (\mathrm{g}) \rightarrow 2 \mathrm{H}_{2} \mathrm{O} \]

This equation tells us that 2 molecules of hydrogen gas react with 1 molecule of oxygen gas to produce 2 molecules of water. This balance is essential as it gives the correct proportions needed for molecules to react without any leftover excess of reactants.

Hydrogen Molecules

In the context of chemical reactions, a molecule is a group of atoms bonded together. Hydrogen molecules are represented by \(\mathrm{H}_{2}\). Each hydrogen molecule is made up of two hydrogen atoms. These molecules are diatomic, meaning each molecule consists of two atoms.

For the reaction of interest, the balanced chemical equation indicates that 2 moles of \(\mathrm{H}_{2}\) are used. This means that for every 2 hydrogen molecules, 1 oxygen molecule will participate in the reaction. In our exercise:

• When using 6 hydrogen molecules, we apply the ratio and find they will react with 3 oxygen molecules.
• This understanding of mole ratios helps us determine how many hydrogen molecules are needed for a complete reaction.

Carefully examining hydrogen's role in chemical reactions gives insight into how gases like hydrogen contribute to forming new compounds.

Oxygen Molecules

Oxygen is another diatomic molecule, similar to hydrogen. It is represented by \(\mathrm{O}_{2}\), where each molecule consists of two oxygen atoms. In chemical equations, oxygen plays a crucial role as a reactant.

In our reaction, we start with 1 mole of \(\mathrm{O}_{2}\), which reacts with 2 moles of \(\mathrm{H}_{2}\).

• This tells us that oxygen molecules are essential in forming the final product, water.
• For every 6 hydrogen molecules reacting, we need 3 oxygen molecules, according to the given ratio.

Understanding the oxygen molecule's behavior helps predict its contribution in forming compounds like water. By ensuring the correct number of oxygen molecules, we allow the reaction to reach completion with no reactant left over.

Water Molecules

The final product of the reaction between hydrogen and oxygen is water, represented as \(\mathrm{H}_{2}\mathrm{O}\). Each water molecule consists of two hydrogen atoms chemically bonded to one oxygen atom. This specific arrangement is what defines a water molecule.

In our balanced chemical equation:

• For every 2 hydrogen molecules reacting with 1 oxygen molecule, 2 water molecules are produced.

Therefore, when 6 molecules of hydrogen react with 3 molecules of oxygen, they will result in the formation of 6 water molecules.

The transformation of hydrogen and oxygen into water demonstrates the principle of chemical reactions where reactants rearrange to form entirely new products. Learning how water molecules form helps us comprehend the fundamental nature of chemical reactions.