Doing what you did is right, as far as you go, BUT it doesn't give you the correct equation.
Multiply equation 1 by 2, including dH for equation 1.
Reverse equation 2 and change sign as you've done.
Add the two. That will give you the equation you want BUT all of the coefficients will be TWICE what you want. Divide by two, including the dH values and you should get it.
Calculate ΔHrxn for the following reaction:
CaO(s)+CO2(g)→CaCO3(s)
Use the following reactions and given ΔH values:
Ca(s)+CO2(g)+1/2O2(g)→CaCO3(s),
ΔH= -812.8 kJ
2Ca(s)+O2(g)→2CaO(s), ΔH= -1269.8 kJ
I have literally tried everything and I don't understand what I am doing wrong, I flipped the last one and changed the sign of the last one and then added them up. still wrong. (-355 is not the correct answer)
1 answer
1 answer