Calculate the mass (in grams) of water vapor produced when 56.0 grams of pure hydrogen gas burn in the air. Given the information from that, calculate the mass of oxygen gas that would be needed to burn 100 grams of hydrogen gas.
write the balanced chemical equation.
Notice the ratio of coefficents of H2 to O2
how many moles of H2 do you have in 100 grams. Do you need half that number of moles of O2? How many grams is that.
To determine the mass of water vapor produced when hydrogen gas burns in the air, we first need to understand the chemical reaction that takes place.
The balanced chemical equation for the combustion of hydrogen gas to form water vapor is as follows:
2H2 (g) + O2 (g) → 2H2O (g)
From the equation, we can see that 2 moles of hydrogen gas react with 1 mole of oxygen gas to produce 2 moles of water vapor. We can use this stoichiometric relationship to calculate the mass of water vapor produced.
Step 1: Convert grams of hydrogen gas (H2) to moles.
Given that we have 56.0 grams of hydrogen gas, we need to find the number of moles using the molar mass of hydrogen gas.
Molar mass of H2 = 2.016 g/mol
Number of moles of H2 = mass (in grams) / molar mass
Number of moles of H2 = 56.0 g / 2.016 g/mol = 27.7777... ≈ 27.8 moles
Step 2: Calculate the moles of water vapor produced.
According to the balanced equation, 2 moles of H2 produce 2 moles of H2O.
Since we have 27.8 moles of H2, the moles of H2O produced will also be 27.8 moles.
Step 3: Convert moles of water vapor to grams.
Now, to calculate the mass of water vapor, we need to multiply the moles of H2O by its molar mass.
Molar mass of H2O = 18.015 g/mol
Mass of water vapor = moles of H2O * molar mass of H2O
Mass of water vapor = 27.8 moles * 18.015 g/mol = 499.767 g ≈ 500 g
Therefore, when 56.0 grams of pure hydrogen gas burns in the air, approximately 500 grams of water vapor are produced.
To calculate the mass of oxygen gas needed to burn 100 grams of hydrogen gas, we can use the same stoichiometric relationship from the balanced equation.
Step 1: Convert grams of hydrogen gas (H2) to moles.
Given that we have 100 grams of hydrogen gas, we need to find the number of moles using the molar mass of hydrogen gas.
Number of moles of H2 = mass (in grams) / molar mass
Number of moles of H2 = 100 g / 2.016 g/mol = 49.6032... ≈ 49.6 moles
Step 2: Calculate the moles of oxygen gas (O2) needed.
According to the balanced equation, 2 moles of H2 react with 1 mole of O2.
So, the moles of O2 needed will be half the moles of H2.
Moles of O2 = 1/2 * moles of H2
Moles of O2 = 1/2 * 49.6 moles = 24.8 moles
Step 3: Convert moles of oxygen gas to grams.
To calculate the mass of oxygen gas, we need to multiply the moles of O2 by its molar mass.
Molar mass of O2 = 32.00 g/mol
Mass of O2 = moles of O2 * molar mass of O2
Mass of O2 = 24.8 moles * 32.00 g/mol = 793.6 g
Therefore, approximately 793.6 grams of oxygen gas would be needed to burn 100 grams of hydrogen gas.