When a balloon filled with 1.249 g of hydrogen explodes, the hydrogen reacts with 9.99 g of oxygen to form water vapor. Assuming water vapor is the only product formed, how much water vapor is produced?
2H2 + O2 ==> 2H2O
1.249 g + 9.99 g = ?
The law of conservation of mass says that you get out what you put in.
To find out how much water vapor is produced when the hydrogen reacts with oxygen, we first need to determine the limiting reactant. The limiting reactant is the reactant that is completely consumed, thereby limiting the amount of product that can be formed.
Step 1: Convert the masses of hydrogen and oxygen to moles.
- Hydrogen (H2): 1.249 g
- Oxygen (O2): 9.99 g
To convert from mass to moles, we use the molar mass of each element:
- Molar mass of hydrogen (H2): 2 g/mol
- Molar mass of oxygen (O2): 32 g/mol
Number of moles of hydrogen (H2):
1.249 g / 2 g/mol = 0.6245 mol
Number of moles of oxygen (O2):
9.99 g / 32 g/mol = 0.3122 mol
Step 2: Use stoichiometry to determine the balanced equation for the reaction between hydrogen and oxygen:
2H2 + O2 -> 2H2O
From the balanced equation, we can see that 2 moles of hydrogen react with 1 mole of oxygen to produce 2 moles of water.
Step 3: Determine the limiting reactant. Compare the number of moles of hydrogen and oxygen to the stoichiometry of the balanced equation.
- Hydrogen (H2): 0.6245 mol
- Oxygen (O2): 0.3122 mol
Since the stoichiometry of the balanced equation indicates that 2 moles of hydrogen react with 1 mole of oxygen, we can see that the oxygen is the limiting reactant because we have less oxygen than is needed for the balanced reaction.
Step 4: Calculate the amount of water vapor produced. Since we determined that oxygen is the limiting reactant, we can use the stoichiometry of the balanced equation.
- Moles of oxygen used: 0.3122 mol (from step 1)
- Moles of water vapor produced: 2 * 0.3122 mol = 0.6244 mol
Step 5: Convert the moles of water vapor to grams using the molar mass of water:
- Molar mass of water (H2O): 18 g/mol
Mass of water vapor produced:
0.6244 mol * 18 g/mol = 11.24 g
Therefore, approximately 11.24 grams of water vapor are produced when the hydrogen reacts with the oxygen.