Question #f723a

1 Answer
Mar 11, 2016

Answer:

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.