## Measuring Heat Transfer

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

### Measuring Heat Transfer

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

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

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

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!