The value of ƒ¢H�‹ for the reaction below is -482 kJ. Calculate the heat (kJ) released to the surroundings when 12.0 g of CO(g) reacts completely.
2CO(g) + O2(g) �¨ 2CO2(g)
482kJ x (12.0/28*2) = ? kJ released.
To calculate the heat (kJ) released to the surroundings when 12.0 g of CO(g) reacts completely, we will follow these steps:
Step 1: Calculate the moles of CO(g) using the given mass and molar mass.
Step 2: Use the stoichiometry of the balanced equation to determine the moles of CO2(g) produced.
Step 3: Use the molar enthalpy change (∆H) of the reaction to calculate the heat released.
Let's begin with Step 1:
1. Calculate the moles of CO(g) using the given mass and molar mass:
The molar mass of CO(g) = 12.01 g/mol + 16.00 g/mol = 28.01 g/mol
Moles of CO(g) = Mass / Molar mass
= 12.0 g / 28.01 g/mol
≈ 0.428 moles
Step 2: Use the stoichiometry of the balanced equation to determine the moles of CO2(g) produced:
From the balanced equation, we can see that 2 moles of CO(g) reacts to form 2 moles of CO2(g).
Since 2 moles of CO(g) produce 2 moles of CO2(g), we can write:
Moles of CO2(g) = Moles of CO(g)
= 0.428 moles
Step 3: Use the molar enthalpy change (ΔH) of the reaction to calculate the heat released:
The molar enthalpy change (∆H) of the reaction is given as -482 kJ.
Heat released = ∆H × Moles of CO2(g)
= -482 kJ × 0.428 moles
≈ -206.296 kJ
Therefore, the heat released to the surroundings when 12.0 g of CO(g) reacts completely is approximately -206.296 kJ. Note that the negative sign indicates that the reaction is exothermic, meaning heat is released to the surroundings.
To calculate the heat released to the surroundings when 12.0 g of CO(g) reacts completely, you need to use the given ΔH° value (-482 kJ) and the molar mass of CO(g) to determine the number of moles of CO(g) present in 12.0 g of CO(g).
1. Calculate the molar mass of CO(g):
The molar mass of carbon (C) is 12.01 g/mol, and the molar mass of oxygen (O) is 16.00 g/mol. Since CO(g) contains one carbon atom and one oxygen atom, the molar mass of CO(g) is 12.01 + 16.00 = 28.01 g/mol.
2. Convert the mass of CO(g) to moles:
Use the formula: number of moles = mass / molar mass
The mass given is 12.0 g, so the number of moles of CO(g) is: 12.0 g / 28.01 g/mol ≈ 0.428 mol.
3. Determine the heat released:
Since the reaction coefficient for CO(g) in the balanced equation is 2, we multiply the number of moles of CO(g) by the ΔH° value and divide by the stoichiometric coefficient (in this case, 2).
Heat released = (0.428 mol CO(g) / 2) * (-482 kJ/mol) = -102.808 kJ.
Therefore, the heat released to the surroundings when 12.0 g of CO(g) reacts completely is approximately -102.808 kJ.