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A 5.1 g piece of gold jewelry is removed from water at 100 degrees celcius and placed...

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spock2 | Student, Undergraduate | (Level 2) Honors

Posted May 7, 2013 at 10:14 AM via web

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A 5.1 g piece of gold jewelry is removed from water at 100 degrees celcius and placed in a coffee-cup calorimeter containing 16.9 g of water at 22.5 degrees celcius. The equilibrium temperature of the water and jewelry is 23.2 degrees celcius. The calorimeter constant is known from calibration experiments to be 1.54 J/degrees celcius (without water). What is the specific heat of the piece of jewelry? Is the jewelry pure gold? 

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pramodpandey | College Teacher | (Level 3) Valedictorian

Posted May 7, 2013 at 11:07 AM (Answer #1)

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By principle of calorimeter,Heat loss is equals to Heat gain.

Gold looses heat and water in coffee cup calorimeter gains heat.

Mass of water cup = 16.9g

Initial temp. of coffee cup water= 22.5 deg. C

Specific heat of water= 4.184 J/g C

Mass of gold =5.1 g

Temp of gold =100 deg C

specific heat of gold =  s   (say) ?

Temp of equilibrium= 23.2 deg C

Calorimeter constant= 1.54 J/C

Heat given by gold =5.1 x s x (100-23.2)

=391.68 s  J

Heat taken by water in coffee cup =16.9 x  4.184 x(23.2-22.5)

 =49.496 J

and

Heat taken by Calorimeter= 1.54 x (23.2-22.5)

=1.078

Heat lost = Heat gain

391.68 s =49.496+1.078

391.68 s=50.574

s=.1291 J/g C

Yes it pure gold.

specific heat of gold= .129 J/(g C)

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