Question #f723a

1 Answer
Mar 11, 2016

Heat capacity of the sample =1.44J//gm//"^oC, rounded to second place in decimal.
Heat capacity of pure gold is known to be =0.129J//gm//"^oC
The value found in the experiment appears exceptionally high.

Explanation:

As the quantities have been given in CGS units, therefore, problem has been worked out in same units. Final answer posted in the asked units.

Value used

Specific heat of water=1cal//gm=4.19kJ//kg

Let the specific heat of the sample =s_s

Amount of heat exchanged is given as DeltaQ=msDeltat,
where m is the mass, s is the specific heat and Deltat is change in temperature.

Heat gained by 15.5gm of water to change from at 24.4^oC to water at 27.0^oC,

DeltaQ_(gai n ed)=msDeltat_w=15.5 times 1times (27.0-24.4)=40.3cal

Simlarly heat lost by 2.58 g of sample is given as
DeltaQ_(lost)=ms_sDeltat_s=2.58xxs_sxx(72.3-27.0)=116.874s_s

Since, DeltaHeat_(lost)= Delta Heat_(gai n ed)

:. 116.874s_s=40.3
implies s_s=40.3/116.874
or s_s=0.34481cal//gm
Changing to desired units. Recall 1 cal=4.184J
Heat capacity of the sample =1.44J//gm//"^oC, rounded to second place in decimal.