How much heat is associated with the burning of 2.27 g of methane in the following unbalanced reaction:
CH4(g) + O2(g) →CO2(g) + H2O(g)?
CH4 + 2O2 ==> CO2 + 2H2O
You must have been given a delta H value.
dH value x (2.27/molar mass CH4) = ?
To determine the amount of heat associated with the burning of 2.27 g of methane, we need to calculate the heat of reaction using the balanced chemical equation and the stoichiometry of the reaction.
Step 1: Write and balance the chemical equation:
CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)
To balance the equation, we need to ensure that the number of each element is the same on both sides:
Carbon: 1 (left) = 1 (right)
Hydrogen: 4 (left) = 4 (right)
Oxygen: 4 (left) = 4 (right)
Step 2: Calculate the molar mass of methane (CH4):
Carbon has an atomic mass of 12.01 g/mol, and hydrogen has an atomic mass of 1.01 g/mol.
Molar mass of methane (CH4) = (12.01 g/mol × 1) + (1.01 g/mol × 4) = 16.05 g/mol
Step 3: Calculate the number of moles of methane (CH4) in 2.27 g:
Number of moles = mass / molar mass
Number of moles = 2.27 g / 16.05 g/mol ≈ 0.1416 mol
Step 4: Use the stoichiometry of the balanced equation to calculate the heat associated with the reaction.
From the balanced equation, we can see that 1 mole of CH4 produces 2 moles of H2O.
Since the reaction is exothermic (heat is released), we can use the coefficient of H2O in the balanced equation to find the heat of reaction.
In this case, 1 mole of CH4 produces 2 moles of H2O, so the heat associated with the reaction is multiplied by the coefficient:
ΔH = 2 moles of H2O × ΔHf of H2O
Step 5: Determine the enthalpy change of formation (ΔHf) of H2O:
The enthalpy change of formation (ΔHf) values are usually given in a reference table. For H2O, it is -285.8 kJ/mol.
Step 6: Calculate the heat associated with the burning of 2.27 g of methane:
ΔH = 2 moles of H2O × ΔHf of H2O
ΔH = 2 × -285.8 kJ/mol ≈ -571.6 kJ
Therefore, the burning of 2.27 g of methane releases approximately -571.6 kJ of heat. Note that the negative sign indicates an exothermic reaction (heat is released).