How much energy is produced when 93.5 grams of oxygen react with 13.2 grams of hydrogen in the following reaction:
2H2+o2-->2 h2o triangleH=-572kJ
To answer this question, we need to first determine which reactant is limiting.
1. Calculate the moles of each reactant:
- Moles of O2 = 93.5 g / 32.00 g/mol = 2.92 mol
- Moles of H2 = 13.2 g / 2.016 g/mol = 6.56 mol
2. Use the mole ratio from the balanced chemical equation to determine which reactant is limiting:
- According to the equation, 2 moles of H2 react with 1 mole of O2
- Therefore, if we assume all of the O2 reacts, we would need 2 * 2.92 = 5.84 moles of H2
- Since we only have 6.56 moles of H2, it is in excess and O2 is limiting.
3. Calculate the amount of energy produced:
- Since we know O2 is limiting, we can use the stoichiometry from the equation to find the moles of water produced:
2 mol of H2O are produced per 1 mol of O2 reacted, so
- Moles of H2O produced = 1/2 * 2.92 mol = 1.46 mol
- Finally, we can use the standard enthalpy change (triangleH) given in the question to calculate the energy produced:
- Energy produced = triangleH * moles of H2O produced
- Energy produced = -572 kJ/mol * 1.46 mol = -835.92 kJ
Therefore, the energy produced by the reaction is -835.92 kJ (the negative sign indicates that the reaction is exothermic, or releases energy).
To determine the amount of energy produced in this reaction, we need to use the stoichiometry of the reaction and the given molar enthalpy change (∆H).
1. Convert the given masses of reactants (oxygen and hydrogen) into moles using their respective molar masses.
- Oxygen (O2):
- Molar mass of O2 = 2 * (16.00 g/mol) = 32.00 g/mol
- Moles of O2 = 93.5 g / 32.00 g/mol = 2.92 mol
- Hydrogen (H2):
- Molar mass of H2 = 2 * (1.01 g/mol) = 2.02 g/mol
- Moles of H2 = 13.2 g / 2.02 g/mol = 6.53 mol
2. Based on the balanced equation, it is given that 2 moles of H2 react with 1 mole of O2.
Since the mole ratio is 2:1, we can see that O2 is the limiting reactant because there are fewer moles of O2 than H2.
3. Calculate the amount of energy produced by the reaction using the stoichiometry and ∆H value.
- 2 moles of H2 produce 2 moles of H2O, and the reaction produces 872 kJ of heat (∆H = -572 kJ).
- Therefore, 1 mole of H2 produces 1 mole of H2O, and the reaction produces 872 kJ of heat (∆H = -572 kJ).
- To calculate the heat energy produced by 2.92 moles of H2, we can set up a proportion:
(2.92 mol H2) / (1 mol H2) = (x kJ) / (872 kJ)
x = (2.92 mol H2) * (872 kJ) / (1 mol H2)
x = 2544.64 kJ
4. Therefore, when 93.5 grams of oxygen react with 13.2 grams of hydrogen, the reaction produces approximately 2544.64 kJ of energy.