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Enthalpy Neutralization watch

1. When calculating the energy transferred I get that you just sub the data given into q=mc(delta T) and then to find the enthalpy change you do q/n(moles) however how do you know what solution you need to work the moles out for.

I have a question asking to work out the enthalpy change of NaOH +H2SO4 but when i worked out the moles of each solution they were different NaOH was 0.02 and H2SO4 was 0.01, I dont know what i divide my q value by. Do I add the moles together? or do I just use one of the solutions?

Sorry if this makes no sense
2. (Original post by lummzie)
When calculating the energy transferred I get that you just sub the data given into q=mc(delta T) and then to find the enthalpy change you do q/n(moles) however how do you know what solution you need to work the moles out for.

I have a question asking to work out the enthalpy change of NaOH +H2SO4 but when i worked out the moles of each solution they were different NaOH was 0.02 and H2SO4 was 0.01, I dont know what i divide my q value by. Do I add the moles together? or do I just use one of the solutions?

Sorry if this makes no sense
the moles should be the same, i would check your calculations for moles again. Volume has to be in dm3.
3. (Original post by sarr99)
the moles should be the same, i would check your calculations for moles again. Volume has to be in dm3.
theres 50cm3 of NaOH with conc of 0.4mol dm3 and 20cm3 of H2SO4 with conc of 0.5 mol dm3.

And the equation for moles is concentration x volume dm. And when I do that for NaOH i get 0.4*(50/1000)= 0.02 and for H2SO4 i get 0.5*(20/1000)= 0.01. I know they should be the same but they're not?
4. I think its because of the different volumes of acid and alkali. Sorry but I'm actually not sure what to do myself.
5. (Original post by lummzie)
When calculating the energy transferred I get that you just sub the data given into q=mc(delta T) and then to find the enthalpy change you do q/n(moles) however how do you know what solution you need to work the moles out for.

I have a question asking to work out the enthalpy change of NaOH +H2SO4 but when i worked out the moles of each solution they were different NaOH was 0.02 and H2SO4 was 0.01, I dont know what i divide my q value by. Do I add the moles together? or do I just use one of the solutions?

Sorry if this makes no sense
If you want the energy change per mole you will have to specify of what.
For neutralisation it is per mole of water formed.

There is complete reaction in this example as 1 mol of sulfuric acid reacts with 2 mol of sodium hydroxide (look at the balanced equation)

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Updated: June 11, 2016
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