Question

Is the reaction `S(s) + 2CO(g) rarr SO_2(g) + 2C(s) + 76*kJ` exothermic?

Answer 1

Absolutely, you got....

`S(s) + 2CO(g) rarr SO_2(g) + 2C(s) + 76*kJ`

Explanation:

Because energy appears as a PRODUCT of the reaction, the reaction is considered `"exothermic"`. Had it been a reactant, we would have classified the reaction as `"endothermic"`.

Another way we could represent this is as:

`S(s) + 2CO(g) rarr SO_2(g) + 2C(s);DeltaH_"reaction"^@=-76*kJ*mol^-1`
...and the enthalpy term is quoted per mole of reaction as written...

And to interpret this another way....a `32*g` mass of sulfur reacts `56*g` of carbon monoxide gas to give a `64*g` mass of sulfur dioxide and `24*g` of carbon.........

AS always, mass is conserved, as it is in every chemical reaction...