q=C delta T


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Alexis Robles 2k
Posts: 100
Joined: Wed Sep 18, 2019 12:18 am

q=C delta T

Postby Alexis Robles 2k » Sun Feb 09, 2020 11:39 pm

What is the difference between q= mCdeltaT and q=CdeltaT? when should we use the m/n in the equation?

Nicholas Chin 1G
Posts: 100
Joined: Thu Jul 11, 2019 12:17 am

Re: q=C delta T

Postby Nicholas Chin 1G » Sun Feb 09, 2020 11:40 pm

The c in q = C * delta T is the heat capacity, measured in Joules per Kelvin. The C in q = m * c* delta T is specific heat capacity, which is measured in Joules per Kelvin gram. The difference is that the first c has different values depending on the amount of some material you have, while the second c only depends on the material you have.

Eugene Chung 3F
Posts: 142
Joined: Wed Nov 15, 2017 3:03 am

Re: q=C delta T

Postby Eugene Chung 3F » Sun Feb 09, 2020 11:42 pm

I think the main difference is whether or not C is given per mol/g or just per T. For example, to calculate q of calorimeter, the question would say that the calorimeter has total heat capacity of 80 j/C, in this case it would just be q= CdeltaT

Prasanna Padmanabham 4I
Posts: 111
Joined: Thu Jul 25, 2019 12:17 am

Re: q=C delta T

Postby Prasanna Padmanabham 4I » Sun Feb 09, 2020 11:47 pm

Alexis Robles 2k wrote:when should we use the m/n in the equation?


Did mean to type: q=n*CdeltaT

If so, n refers to mols while m refers to grams...you would use whatever units the question asked for...

805394719
Posts: 104
Joined: Wed Sep 11, 2019 12:16 am

Re: q=C delta T

Postby 805394719 » Sun Feb 09, 2020 11:58 pm

q = C delta T gives the heat capacity whereas q = m C delta T gives the specific heat per 1 gram of the substance since there is multiplication with the grams of the substance.

nicolely2F
Posts: 149
Joined: Sat Sep 14, 2019 12:17 am

Re: q=C delta T

Postby nicolely2F » Sun Feb 09, 2020 11:58 pm

You should use a different notation because these equations are different things. The variable Cs (sometimes denoted as c) stands for specific heat capacity, the heat required to change the temperature of 1 gram of a substance by +1°C. The variable C stands for heat capacity, the heat required to change the temperature of a certain object / mass m of a substance by +1°C. Thus:
q = C.ΔT
and
q = m.Cs.ΔT


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