Measuring Heat Transfer

Moderators: Chem_Mod, Chem_Admin

Meghna Patel 2L
Posts: 13
Joined: Wed Sep 21, 2016 2:59 pm

Measuring Heat Transfer

Postby Meghna Patel 2L » Sun Jan 22, 2017 7:25 pm

For the questions about measuring heat transfer, why is it that the equations for delta H are sometimes mC(delta T) and some are nC(delta T)? How would you know which equation to use?

LeontyneHenderson2E
Posts: 16
Joined: Wed Sep 21, 2016 2:57 pm

Re: Measuring Heat Transfer

Postby LeontyneHenderson2E » Sun Jan 22, 2017 7:33 pm

Are delta U, q, and delta H essentially measuring the same thing?

Arianna_Mandelli_3C
Posts: 10
Joined: Wed Sep 21, 2016 2:58 pm

Re: Measuring Heat Transfer

Postby Arianna_Mandelli_3C » Sun Jan 22, 2017 7:38 pm

The equation with the m in it will give you the energy supplied as heat to the substance, and the equation with the n in it will give you the molar heat capacity of a substance. The m refers to mass while the n refers to moles. You'll know which equation to use based on which one (grams or moles) the problem gives you.

YuniLee_1K
Posts: 23
Joined: Wed Sep 21, 2016 2:59 pm

Re: Measuring Heat Transfer

Postby YuniLee_1K » Tue Jan 24, 2017 12:40 am

Delta U is only equal to delta H when the volume of reactants equals the volume of products. This is because since q = delta H at constant pressure (aka qp = delta H), delta U = qp + w, and w = 0 when the volumes are equal, delta U = qp + w = delta H + w = delta H. Hope this helped!


Return to “Thermodynamic Systems (Open, Closed, Isolated)”

Who is online

Users browsing this forum: No registered users and 0 guests