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November 01, 2025, 01:15:43 pm
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Author Topic: Enthalpy Questions  (Read 631 times)  Share 

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cltf

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Enthalpy Questions
« on: August 19, 2011, 10:38:35 pm »
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In an exothermic acid base reaction that heats water, say 50ml of 2M HCL and 50ml 2M NaOH were mixed, and a 12.8 degree temperature change was observed.
When calculating E=SHC x Mass x Temp Change, do we assume the mass is 50g or 100g given density is 1g/ml?
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HenryP

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Re: Enthalpy Questions
« Reply #1 on: August 19, 2011, 10:53:16 pm »
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You would have to use 100 since its the combined volume of both the liquids.
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Re: Enthalpy Questions
« Reply #2 on: August 21, 2011, 12:04:24 am »
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You need to be careful because if you do that you need to realise your interpreting the energy value as the energy released by 2 reactants. In combustion cases (which you are likely to be more familiar with) it only concerns the combustible material and not oxygen. So make sure you know what your doing when you consider the energy value if it corresponds to both reactants.

Thank you
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