In the explosion of a hydrogen-filled balloon, 0.75 g of hydrogen reacted with 6.9 g of oxygen to form how many grams of water vapor? (Water vapor is the only product.)
I am really confused on how to do this.
H2+O2->H2O
balance the equation:
2H2+O2->2H2O
now using the balance equation, find how many grams of water vapor is formed? (hint: this is a limiting agent problem)
-find number of grams of H2O produced from .75g H2
-find number of grams of H2O produced from 6.9g O2
-which number is smaller? (that's the limiting reagent & that's how many grams of water vapor form!)
To determine the number of grams of water vapor formed in the given reaction, we need to follow a few steps.
Step 1: Write the balanced chemical equation for the reaction. In this case, we know that the reactants are hydrogen (H2) and oxygen (O2), and the product is water (H2O). The balanced equation is:
2H2 + O2 -> 2H2O
Step 2: Calculate the moles of hydrogen and oxygen used in the reaction. To find the moles, use the formula:
moles = mass (g) / molar mass (g/mol)
The molar mass of hydrogen (H2) is 2.02 g/mol, and the molar mass of oxygen (O2) is 32.00 g/mol.
moles of hydrogen = 0.75 g / 2.02 g/mol
= 0.371 mol
moles of oxygen = 6.9 g / 32.00 g/mol
= 0.216 mol
Step 3: Determine the limiting reactant. The limiting reactant is the one that is completely consumed in the reaction, thereby limiting the amount of product formed. To determine the limiting reactant, compare the moles of each reactant to the stoichiometric ratio in the balanced equation (2H2: 1O2).
Using the stoichiometry, we find that 2 moles of hydrogen (H2) react with 1 mole of oxygen (O2). This means that if we have 0.371 moles of hydrogen, we would need 0.1855 moles of oxygen to consume all the hydrogen completely. However, we only have 0.216 moles of oxygen, which is more than enough. Therefore, oxygen is the limiting reactant.
Step 4: Calculate the moles of water vapor formed. Since oxygen is the limiting reactant, we can use the stoichiometric ratio of the balanced equation to determine the moles of water produced.
From the balanced equation, we see that 2 moles of water (H2O) are formed from 1 mole of oxygen (O2).
Therefore, moles of water vapor = 0.216 mol O2 x (2 mol H2O / 1 mol O2)
= 0.432 mol
Step 5: Calculate the mass of water vapor formed. To find the mass, use the formula:
mass = moles x molar mass
The molar mass of water (H2O) is 18.02 g/mol.
mass of water vapor = 0.432 mol H2O x 18.02 g/mol
= 7.796 g
Therefore, the grams of water vapor formed in the reaction are approximately 7.796 g.