# Chemistry

posted by .

Calculate the enthalpy change for the reaction 2C + H2 yield C2H2 given the following reactions and their respective enthalpy changes:

C2H2 + 5/2 O2 yield 2CO + H2O -1299.6
C + O yield CO2 -393.5
H2 + 1/2 O2 yield H2O -285.9

I don't even know how to start and the example in the book doesn't explain anything!!!!

• Chemistry -

Look in your text about Hess' Law. That is what this problem is. The idea is to multiply (if necessary) an equation AND/OR reverse it so that all of them added together will give you the final equation you want.
If you get stuck let us know what you don't understand (be specific---; i.e., I don't know where to start or I don't have a clue doesn't help us determine the problem you are having.)

• Chemistry -

Check you post carefully. I don't think all of the equations you have written are balanced. For example, look at the ones with CO. Are those CO2?

## Similar Questions

1. ### Chemistry

Calculate the enthalpy change for the reaction 2C (s) + H2 (g) yield C2H2 (g) given the following reactions and their respective enthalpy changes: C2H2(g) + 5/2 O2(g) yield 2CO2(g) + H2O (l) = -1299.6kJ C(s) + O2(g) yield CO2 (g) -393.5 …
2. ### AP CHEMISTRY NEED HELP PLEASE!

Calculate the enthalpy of combustion of C3H6: C3H6 (g) + 9/2 O2 (g) yield 3CO2 + 3H2O using the following data: 3C (s) + 3H2 (g) yield C3H6 (g) change in H= 53.3 kJ C(s)+O2 (g) yield CO2 (g) change in H= -394kJ H2 (g) + 1/2 O2 (g) …
3. ### Chemistry

Reposted: Use Hess's law to calculate the enthalpy change for the reaction: 3C(s) + 3H2(g) yield C3H6(g) Given the following thermochemical equations: 2C3H6(g) + 9O2(g) yield 6CO2(g) + 6H2O(l) enthalpy change= -4116.0 kJ/mol C(s) + …
4. ### Chemistry

Please explain. The enthalpy changes for two different hydrogenation reactions of C2H2 are: C2H2+H2---->C2H4 Delta H 1 C2H2+2H2---->C2H6 Delta H 2 Which expression represents the enthalpy change for the reaction below?
5. ### CHEMISTRY

Please explain. The enthalpy changes for two different hydrogenation reactions of C2H2 are: C2H2+H2---->C2H4 Delta H 1 C2H2+2H2---->C2H6 Delta H 2 Which expression represents the enthalpy change for the reaction below?
6. ### CHEMISTRY

I know I posted this question before, but can you clarify it?
7. ### Chemistry

I know I posted this question before, but can you clarify it?
8. ### Chemistry

Acetylene gas, C2H2, reacts with oxygen according to the following equation. If 46.0 g of acetylene reacts with 100.0 g of oxygen, what is the theoretical yield of heat produced from the reaction?
9. ### Chemistry

Oxyacetylene torches are fueled by the combustion of acetylene, C2H2. 2C2H2(g) + 5O2(g) --> 4 CO2(g) + 2H2O(g) If the enthalpy change for the reaction is -2511.14 kJ/molrxn, how much heat can be produced by the reaction of a. 2mol …
10. ### Chemistry

In a laboratory, the following reaction is performed by combining 358 g of H2O and a sufficient amount of CaC2. The percent yield for this reaction is 94.5%. Calculate the actual yield of acetylene (C2H2) in grams from this reaction. …

More Similar Questions