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bond enthalpy question help

Hey people, I'm doing a bond enthalpy question in the OCR A textbook, in chapter 9.3 about bond enthalpies, and it's specifically Question 3 of the summary questions I need help with.

Q3 gives the equation 2SO2(g) + O2(g) -> 2SO3(g) and the enthalpy change for the reaction is -192 kJ mol-1. It's asking you to assume that SO2 and SO3 only have S=O bonds.

There are no values given for the SO bonds, but the value for O=O in O2 is 498 kJ mol-1. I'm having a headache figuring out the value for the SO bond,

I only managed to get an equation : 4x + 498 -> 6y and I haven't a clue where to go from here.

Any help is appreciated. Thanks.

Reply 1

avacados1

In the question it gives u the enthalpy change as -192 so u know the sum of the average bond enthalpy of SO2 and O2 minus SO3 = -192 kJ mol-1 . Also why are u using two different variable x and y when the SO bond stays the same and so only one variable should he used for both.