Energy required for temperature raise  temperaturedependent specific heat capacityby davidray Tags: heat capacity, moles, thermal physics 

#1
Oct1711, 06:09 AM

P: 7

Any help on this quistion would be greatly appreciated. I have no idea ho to answere it, and can't find anything in my nothes or books anywhere.
The temperaturedependent molar specific heat capacity at constant pressure of many substances is given by: c =a+2bT−cT^−2 For magnesium, the numerical values of the constants are: a=25.7, b=3.13x10^3, c=3.27x10^5 where c has units J/Kxmol Calculate the energy required to raise the temperature of 15g of Megnesium from 30 C to 300 C. I have tried using the formula to qenerate a specific heat capacity for each temperature, but just seem to get crazy numbers that don't make any sense! Thanks for the help! 



#2
Oct1711, 02:47 PM

P: 688

You can find the average value of the specific heat over the temperature range from:
C_avg = [itex]\frac{1}{TfTo}[/itex][itex]\int[/itex][itex]\frac{To}{Tf}[/itex]C(T) dt Then compute the energy from: E = m C_avg (Tf  Ti) 



#3
Oct1711, 11:56 PM

P: 2

any help for the following qestion will be appriciated
15mm thick concrete slab have an electric underfloor heater running in off peak time and release storage heat during day time then how much time its to reduce temp. from 23.5 at6:00am to 21 degree and with the variable outside temp. during day.outside temp is 8 degree and reuire temp. 19 at 6:00am and heat transfer output is 41.62w/m2 and how much time its to increse the temp during running off peak time 



#4
Oct1711, 11:58 PM

P: 2

Energy required for temperature raise  temperaturedependent specific heat capacity 


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