The amount of energy released by the combustiom of 100 g of C2H2 (g) is ______ MJ.
2CH2 + 5O2 ----> 4CO2(g) + 2H2O(g) ΔH= -2511.0 kJ
Do I use ΔH = Hproducts - Hreactants? And if so how would that help me solve for the energy released?
Yes, you can use the equation ΔH = Hproducts - Hreactants to solve for the energy released in the combustion reaction. In this case, the given ΔH value of -2511.0 kJ represents the heat of the reaction.
To find the amount of energy released by the combustion of 100 g of C2H2 (g), you should first convert the given mass (100 g) of C2H2 to moles. To do this, you need to know the molar mass of C2H2:
C2H2:
C: atomic mass = 12.0 g/mol
H: atomic mass = 1.0 g/mol
Total molar mass of C2H2 = (2 * 12.0) + (2 * 1.0) = 26.0 g/mol
Now, using the molar mass of C2H2, you can calculate the number of moles of C2H2 present in 100 g of C2H2:
Number of moles = mass / molar mass = 100 g / 26.0 g/mol = 3.85 mol (rounded to two decimal places)
Since the balanced equation shows that 2 moles of C2H2 release -2511.0 kJ of energy, you can set up a proportion to find the energy released by 3.85 moles of C2H2:
(3.85 mol C2H2 / 2 mol C2H2) = (ΔH / X)
By cross-multiplying and solving for "X" (the energy released), you can find the answer.
X = (3.85 mol C2H2 / 2 mol C2H2) * (ΔH / 1)
Finally, substitute the given ΔH value of -2511.0 kJ into the equation to calculate the energy released:
X = (3.85 mol C2H2 / 2 mol C2H2) * (-2511.0 kJ / 1) = -4839.79 kJ (rounded to two decimal places)
Therefore, the amount of energy released by the combustion of 100 g of C2H2 (g) is approximately -4839.79 kJ.
I'm assuming the CH2 should be C2H2 (Acetylene) ...
From the balanced equation, two moles of acetylene => -2511Kj = 2.511Mj
Convert 100g C2H2 to moles 100g/26g/mol = 3.85 moles
Set ratio ...
(2/3.85 = 2.511/x => x = [(2)(2.511)]/(3.85)Mj = 1.30Mj
No and yes.
You don't need to use dHrxn = (n*dHf products) - (n*dHf reactants) because the problems has already done that for you. For the reaction given dH is -2511.0 kJ and that is for 2 mols of C2H2 or 2*26 = 52 g.
So the revised question is if 52 g releases 2511.0 kJ how much will 100 g release? Can you take it from there?
Well, if you're burning 100 g of C2H2 (g), you'll need to use the molar mass of C2H2 to calculate the number of moles first. Then, using the balanced equation and the stoichiometric coefficients, you can calculate the moles of CO2 and H2O produced.
Once you have the moles of the products, you can use the given enthalpy change, ΔH = -2511.0 kJ, and the equation ΔH = Hproducts - Hreactants. Just make sure you're using the right signs for the reactants and products.
Now comes the fun part! Since you're looking for the energy released, you need to multiply the moles of CO2 and H2O produced by the enthalpy change (-2511.0 kJ) and convert it to MJ (mega joule).
Don't forget to put on your "safety humor goggles" while performing these calculations! And remember, it's better to be a "safety clown" than a "sad clown" when dealing with some explosive chemistry!
Yes, you are correct. To solve for the energy released during combustion, you can use the equation: ΔH = Hproducts - Hreactants.
In this case, the equation you provided is the balanced equation for the combustion of C2H2. The ΔH value given (-2511.0 kJ) represents the enthalpy change of the reaction.
To find the energy released by the combustion of 100 g of C2H2, you need to calculate the amount of moles of C2H2 and then use the stoichiometry of the reaction to find the energy released.
1. Calculate the moles of C2H2:
- Molar mass of C2H2 = (2 * atomic mass of C) + (2 * atomic mass of H) = (2 * 12.01 g/mol) + (2 * 1.01 g/mol) = 26.04 g/mol
- Moles of C2H2 = (mass of C2H2) / (molar mass of C2H2) = 100 g / 26.04 g/mol
2. Use stoichiometry to find the energy released:
- From the balanced equation, you can see that the stoichiometric coefficient of C2H2 is 2.
- ΔH is given per 2 moles of C2H2, so to find the energy released for 1 mole of C2H2, divide ΔH by 2: ΔH = -2511.0 kJ / 2
- Multiply ΔH by the moles of C2H2: Energy released = (ΔH) * (moles of C2H2)
3. Convert the energy released to MJ:
- Divide the energy released by 1000 to convert from kJ to MJ: Energy released (MJ) = (Energy released / 1000)
By following these steps, you will be able to calculate the amount of energy released during the combustion of 100 g of C2H2.