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PLEASE HELP question involving heat exchange

notassmartasiwi
1-Newbie

PLEASE HELP question involving heat exchange

the question was

"A hard boiled egg with a heat capacity of 2.0x10^3 J/Kg'C and a mass of 50g is cooled from 100'C by 1L of water at 5'C. What will be the final temperature of the water and the egg after they have been allowed to sait for a few moments.?"

this is what I know:
The egg
Eh or Q= 2.4x10^3 J/Kg'C
m1=50g which is 0.05Kg
t1=100'C
t2=?
c=?
The water
m=? ->(are you suppose to change 1L into a mass? if yes how so?Fo you use density or something?)
t1=5'C
t2=?
Q=4.18x10^3J/Kg'C(i got this from my textbook)

I also know:
(m1)(c1)(delta t)=-(m2)(c2)(delta t2)

Q=(m)(c)(delta t)

Can you set me on the right track, please?

1 REPLY 1

On 11/4/2002 8:42:00 PM, notassmartasiwishiwas wrote:
>the question was
>
>"A hard boiled egg with a heat
>capacity of 2.0x10^3 J/Kg'C
>and a mass of 50g is cooled
>from 100'C by 1L of water at
>5'C. What will be the final
>temperature of the water and
>the egg after they have been
>allowed to sait for a few
>moments.?"
>
>this is what I know:
>The egg
>Eh or Q= 2.4x10^3 J/Kg'C
>m1=50g which is 0.05Kg
>t1=100'C
>t2=?
>c=?
>The water
>m=? ->(are you suppose to
>change 1L into a mass? if yes
>how so?Fo you use density or
>something?)
>t1=5'C
>t2=?
>Q=4.18x10^3J/Kg'C(i got this
>from my textbook)
>
>I also know:
>(m1)(c1)(delta
>t)=-(m2)(c2)(delta t2)
>
>Q=(m)(c)(delta t)
>
>Can you set me on the right
>track, please?
>


Since the final temperature must be at least 5C, the excess heat given by (100-5)*q_egg*m_egg is the excess heat that must be distributed to q_egg*m_egg+q_water*m_water. You might be able to get away with ignoring the egg afterwards, but it's sloppy science.

As for the mass of the water, remember that water is almost exactly 1 gm/ml

TTFN
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