Enthalpy of Rxn

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eduardomorales5
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Enthalpy of Rxn

Postby eduardomorales5 » Sat Feb 01, 2020 1:42 pm

If the enthalpy of a reaction is 300kJ/mol, and we have 0.05mol of th substance, do we multiply or divide by the moles of the substance to find the enthalpy of the reaction?

Haley Dveirin 1E
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Re: Enthalpy of Rxn

Postby Haley Dveirin 1E » Sat Feb 01, 2020 1:57 pm

Multiply

Sofia Ban
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Joined: Fri Sep 28, 2018 12:25 am

Re: Enthalpy of Rxn

Postby Sofia Ban » Sat Feb 01, 2020 3:00 pm

You would multiply 300kJ/mol by the 0.05 mol since we are trying to get rid of the mol unit. Keep in mind we are trying to find the enthalpy of the reaction which the units are in joules.

preyasikumar_2L
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Re: Enthalpy of Rxn

Postby preyasikumar_2L » Sat Feb 01, 2020 3:01 pm

You multiply 300kJ/mol by 0.05 mol to get the mol units to cancel out and get a result of 15 kJ for the enthalpy of reaction.

Nicholas_Gladkov_2J
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Re: Enthalpy of Rxn

Postby Nicholas_Gladkov_2J » Sat Feb 01, 2020 6:53 pm

eduardomorales5 wrote:If the enthalpy of a reaction is 300kJ/mol, and we have 0.05mol of th substance, do we multiply or divide by the moles of the substance to find the enthalpy of the reaction?


Usually if I'm stuck on deciding whether not to multiply or divide I look at the units. Think about what units you want in the end and the units that you have now. Think about how you can manipulate the two to cancel, resulting in the units you want.

In your case, you would multiply.

Kate Swertfager
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Re: Enthalpy of Rxn

Postby Kate Swertfager » Sun Feb 02, 2020 6:09 pm

Multiply. Also always look at the units for help. You need moles to cancel

Emily Burghart 1k
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Re: Enthalpy of Rxn

Postby Emily Burghart 1k » Sun Feb 02, 2020 8:25 pm





As you can see here, you will want to multiply the values to cancel out the mol, so you are left with kJ. You are left with 15kJ.

Anokhi Patel 2B
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Re: Enthalpy of Rxn

Postby Anokhi Patel 2B » Sun Feb 02, 2020 8:44 pm

you just multiply the enthalpy of the reaction by the moles to cancel out the reaction

Alexandra Bartolome 2H
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Re: Enthalpy of Rxn

Postby Alexandra Bartolome 2H » Sun Feb 02, 2020 10:20 pm

You would multiply so that the moles cancel out and you are left with the units kJ.

Bryan Chen 1H
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Joined: Mon Jun 17, 2019 7:24 am

Re: Enthalpy of Rxn

Postby Bryan Chen 1H » Sun Feb 02, 2020 10:22 pm

i personally dont think about multiplying or dividing, i look at the units of each (kJ, and kJ/mole), and i try to format it so the units cancel. i think its called dimensional analysis or something


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