Enthalpy question - Urgent!!
I have an exam tomorrow and I am completely stuck on this:
How do you know whether to add or take away the enthalpy change when you are trying to find the enthalpy change of formation or combustion (or any other type of enthalpy change)?
Does the type of enthalpy change (e.g. formation or combustion) change whether you add or minus the ΔH?
Is there just a general rule that I should use?
This is a question I was doing, but I am not sure what to do:
Hydrogen reacts with chlorine to form hydrogen chloride, HCl:
H2(g) + Cl2(g) → 2HCl(g)
ΔH = −184 kJ mol−1
Bond Enthalpy / kJ mol−1
H−H = +436
Cl−Cl +243
Calculate the bond enthalpy for the H–Cl bond
Thank you!
How do you know whether to add or take away the enthalpy change when you are trying to find the enthalpy change of formation or combustion (or any other type of enthalpy change)?
Does the type of enthalpy change (e.g. formation or combustion) change whether you add or minus the ΔH?
Is there just a general rule that I should use?
This is a question I was doing, but I am not sure what to do:
Hydrogen reacts with chlorine to form hydrogen chloride, HCl:
H2(g) + Cl2(g) → 2HCl(g)
ΔH = −184 kJ mol−1
Bond Enthalpy / kJ mol−1
H−H = +436
Cl−Cl +243
Calculate the bond enthalpy for the H–Cl bond
Thank you!
(edited 10 months ago)
if you’re provided the enthalpy of formation for the molecules then it’s products - reactants. If you’re provided the enthalpy change of combustion it is reactants - products
Idk if that answers your question lol but it’s what I use
I think if you apply this it should get you the right answer if you don’t make any silly mistakes like forgetting a bond
Idk if that answers your question lol but it’s what I use
I think if you apply this it should get you the right answer if you don’t make any silly mistakes like forgetting a bond
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