[darkangel1]

Hi,

I have to solve this problem here before next week, but I do not know where I should beginn and how I should solve this problem. I am a biginner concerning physical chemistry.

Here is the problem :

On arousal from hibernation, a hamster can raise its body temperature by as much as 30K. Assuming that the heat required for this arises from combustion of fatty acids calculate the weight of fatty acid which would be needed to be oxidised in order to warm up a 100 g hamster.
The delta U for combustion (in the presence of O2 to CO2 and HOH) of solid stearic acid is -11360 kJ/mol - thus you must consider the delta n in order to calculate the corresponding delta H.

The molecular formula of stearic acid is C18H36O2
R = 8.31 J/Kmol
The specific heat of the hamster tissue is 3.30 J/Kg

I would be thankfull if anyone could explain me what to do and how to solve this problem in easy steps.

Thank you in advance!

[Borek]

Do you know what heat balance is?

[darkangel1]

No, not really. Can you give me an hint?

[Borek]

heat lost = heat gained

Your hamster need to gain enough heat to get warm. First you must calculate how much heat it needs using methods used for heat balance calculations. Google.

[darkangel1]

Hi, I googled, but only found progams that calculate. Next week I must explain it in front of the blackboard. I mean I still did not figure out how it goes. The professor gaves us the hint to consider deltaG = deltaH - TdeltaS.

Physical chemistry is a complete new topic for me and it would be great if someone could explain me the solution to this problem.

[Donaldson Tan]

What is the amount of heat (Q) needed to raise the body temperature of a 100g (m) hamster by 30K (dT) since you already know its heat capacity (Cp)? Hint: Q = m.Cp.dT

How much fat (m_fat) do you need to generate that amount of heat (Q)?

[ua_sinan]

if u help me about this problem i will pray everyday for u

the vapor pressure of a liquid in the temperature range 200 K to 260 K was found to fit the equation:   

               ln(p/torr)=18.361 -- 3036.8/(T/K)

calculate the enthalpy of vaporization of the liquid!!!

the answer=25.25 kj/mol