Posted by **mohd** on Sunday, April 11, 2010 at 3:57pm.

these are my three thermochemical equations

2Cu(s)+S(s) give Cu_2S(s) delta H -79.5 KJ

S(s)+O_2 give SO_2(g) -297 KJ

Cu_2S(s)+2O_2(g) give 2CuO(s)+SO_2(g)

how i calculate standard enthalpy of formation in Kj per mol of CuO(s)?

please don't give the answer only guid me please

- chemistry -
**DrBob222**, Sunday, April 11, 2010 at 4:06pm
Add equation 1 to the reverse of equation 2 to equation 3. That will give you twice the equation you want and you can take half of it later.

Add kJ/mole for equation to the negative of equation 2 to the kJ for equation 3. All of that together gives twice what you are looking for so divide the total by 2 and divide the equation by 2.

- chemistry -
**mohd**, Sunday, April 11, 2010 at 4:12pm
in front of last equation i forgat to wright the delta H .it is -527.5 KJ

- chemistry -
**DrBob222**, Sunday, April 11, 2010 at 4:14pm
That doesn't change anything. When you reverse an equation change the sign of delta H, otherwise leave it.

## Answer This Question

## Related Questions

- Chemistry - Given: Cu2O(s) + 1/2 O2(g) → 2CuO(s) deltaHÂ°= -144 kJ 2Cu2O(s...
- chemistry 211 Lamar Univ - Calculate the number of SO_2 molecules in 9.19 moles ...
- Chemistry - Copper metal can be obtained by heating copper oxide in the presence...
- Chemistry - The following reaction has a standard enthalpy of reaction of -146.0...
- chemistry - Given the following thermochemical equations, NO(g) + (1/2) Cl2(g...
- chemistry - Given the following thermochemical equations, NO(g) + (1/2) Cl2(g...
- chemistry - The equations for the heats of the formation of copper (I) oxide,...
- chemistry - The standard enthalpy of combustion of C2H6O(l) is -1,367 kJ mol-1 ...
- Chemistry - Consider the isomerization equlibria of an alkene (C4H8) that co-...
- Chemistry - 1.What is the molar heat of vaporization of water, given the ...

More Related Questions