To determine how many moles of oxygen are required to react completely with 1.2 grams of hydrogen, we can follow these steps:
-
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).
\[ \text{Moles of } H_2 = \frac{\text{mass of } H_2}{\text{molar mass of } H_2} = \frac{1.2 \text{ g}}{2.02 \text{ g/mol}} \approx 0.594 \text{ moles} \]
-
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.
-
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.