| Lab 4 of 2LB|In-Class Test| Lab 6 of 2LB|
Lab 5 of 2LB
Lab 8 of 40B
Specific Heat of Metals
Courtesy of Yeuh-feng Chiang
1. Latent Heat of Liquid Nitrogen
The measured voltage and current are:
V = ______, Unit:( )
P = I V =__________ Watt =___________( cal/sec)
|
Time (sec) |
Mass (g) |
Time (sec) |
Mass (g) |
|
-30 |
80 |
||
|
-20 |
90 |
||
|
-10 |
100 |
||
|
0 |
110 |
||
|
10 |
120 |
||
|
20 |
130 |
||
|
30 |
140 |
||
|
40 |
150 |
||
|
50 |
160 |
||
|
60 |
170 |
||
|
70 |
D M = _____, Unit:( )
D t = ______, Unit:( )
L = ( PD t )/D M = _______, Unit:( )
Compare the calculated value of L with "standard " value of 47.8 cal/g
2. Specific heat of Metals
|
Massmetal, (g) |
MassAluminum= |
MassCopper= |
MassLead= |
|
Time (sec) |
MassN2 (g) |
MassN2 (g) |
MassN2 (g) |
Time (sec) |
MassN2 (g) |
MassN2 (g) |
MassN2 (g) |
|
-60 |
30 |
||||||
|
-50 |
40 |
||||||
|
-40 |
50 |
||||||
|
-30 |
60 |
||||||
|
-20 |
70 |
||||||
|
-10 |
80 |
||||||
|
0 |
90 |
||||||
|
10 |
100 |
||||||
|
20 |
110 |
D T =(Troom-TN2) = _________, Unit:( )
cmetal = ( MN2L )/( MmetalD T )
Record your final result in the following table:
|
Massmetal |
MassN2 |
c v= cmetal |
Atomic weight |
Experimental Molar Cv |
%ERROR |
| MAluminum= |
|
c Aluminum = |
26.98 |
% | |
| Mcopper= |
|
ccopper = | 63.55 |
% | |
| Mlead= |
|
c Lead = | 207.19 |
% |
Question: How do the results compare with the theoretical value, 3R = 24.94 ( J/mol-K ) = 5.96 ( cal/mol-K )?
(1.5 points) Fill out the last column of the above data table.
(0.5 point) Write down one of the possible sources of the systematic error with a logical reason and a numerical estimation. Any simple answer implying "Human Error" or "Stupidity" is totally unaccpetable!
| Lab 4 of 2LB|In-Class Test| Lab 6 of 2LB|
