Number 99 of Chemistry Lecture 4 (page 82)

[masterMood]

How is it possible that say 50 g of a substance can have the same amount of energy as 50 g of the same substance at a different temperature?

For instance:

50 grams of Gold can absorb 100 joules of energy at 25 degrees Celsisu and at 50 degrees Celsius will absorb 100 joules of energy too.

EK says that this is probably a little too complex to be on the MCAT but I am curious seeing as the equation is

Q= C*delta T

and Q = mc*delta T, judging on that equation alone, it seems that increasing temperature is always proportional to the increase in heat.

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[seraph524]

Hrmm...I guess an easy cop-out answer would be to use Einstein's E=mc^2 equation. The equation only cares about mass of the object, not the temperature.

Although, it has been like 4 years since I took physics, maybe I'm using the equation wrong? Any physics-gurus out there? (paging physics junkie!)

 

[masterMood]

well if a physics major who is an MD/PHD doesn't really know this, then I'm gonna say banchod **** you hiramzeddah EK for asking ccrap that isn't gonna beo n it (unless it's in a passage and inferable from it).

 

[unsung]

How is it possible that say 50 g of a substance can have the same amount of energy as 50 g of the same substance at a different temperature?

For instance:

50 grams of Gold can absorb 100 joules of energy at 25 degrees Celsisu and at 50 degrees Celsius will absorb 100 joules of energy too.

EK says that this is probably a little too complex to be on the MCAT but I am curious seeing as the equation is

Q= C*delta T

and Q = mc*delta T, judging on that equation alone, it seems that increasing temperature is always proportional to the increase in heat.

I think the heat capacity of a substance is actually supposed to vary a little with temperature, although for the MCAT, we're supposed to assume it's a constant for all temps. Perhaps that's it?

 

[Heyeon]

Perhaps because the volume remains fairly constant so the molar heat capacity is constant..ie 100 J