Question
Given 2H2 + O2 --> 2H2O. How many moles of oxygen are required to react completely with 1.2 grams of hydrogen to form water?
Answers
GPT-4o mini
To determine how many moles of oxygen are required to react completely with 1.2 grams of hydrogen, we can follow these steps:
1. **Calculate the number of moles of hydrogen (H₂)**:
The molar mass of hydrogen (H₂) is approximately 2.02 g/mol (since each H atom is about 1.01 g/mol, and there are 2 H atoms in H₂).
\[
\text{Moles of } H_2 = \frac{\text{mass of } H_2}{\text{molar mass of } H_2} = \frac{1.2 \text{ g}}{2.02 \text{ g/mol}} \approx 0.594 \text{ moles}
\]
2. **Use the balanced chemical equation**:
The balanced reaction is:
\[
2H_2 + O_2 \rightarrow 2H_2O
\]
From the equation, we see that 2 moles of hydrogen react with 1 mole of oxygen.
3. **Determine moles of oxygen needed**:
Since 2 moles of hydrogen require 1 mole of oxygen, the ratio of hydrogen to oxygen is 2:1. Therefore, to find the moles of oxygen required for the moles of hydrogen calculated, we can use this ratio:
\[
\text{Moles of } O_2 = \frac{0.594 \, \text{moles of } H_2}{2} \approx 0.297 \text{ moles of } O_2
\]
Thus, approximately **0.297 moles of oxygen** are required to react completely with 1.2 grams of hydrogen to form water.
1. **Calculate the number of moles of hydrogen (H₂)**:
The molar mass of hydrogen (H₂) is approximately 2.02 g/mol (since each H atom is about 1.01 g/mol, and there are 2 H atoms in H₂).
\[
\text{Moles of } H_2 = \frac{\text{mass of } H_2}{\text{molar mass of } H_2} = \frac{1.2 \text{ g}}{2.02 \text{ g/mol}} \approx 0.594 \text{ moles}
\]
2. **Use the balanced chemical equation**:
The balanced reaction is:
\[
2H_2 + O_2 \rightarrow 2H_2O
\]
From the equation, we see that 2 moles of hydrogen react with 1 mole of oxygen.
3. **Determine moles of oxygen needed**:
Since 2 moles of hydrogen require 1 mole of oxygen, the ratio of hydrogen to oxygen is 2:1. Therefore, to find the moles of oxygen required for the moles of hydrogen calculated, we can use this ratio:
\[
\text{Moles of } O_2 = \frac{0.594 \, \text{moles of } H_2}{2} \approx 0.297 \text{ moles of } O_2
\]
Thus, approximately **0.297 moles of oxygen** are required to react completely with 1.2 grams of hydrogen to form water.