Specific Heat
Equipment
| Blocks |
U 40860 |
| Thermometer |
000916 |
| Stopwatch |
001079 |
| Plastic Lid |
000585 |
| Hotplate |
000730 |
| Computer |
100811 |
Data
For both systems, the following are known constants.
| CH2O |
1.0 cal/g ÁC |
| Cstirrer |
0.092cal/ g ÁC |
| Mcup |
57.13g |
| Mstirrer (Brass) |
17.06g |
The following data reflects the data collected while working with the iron block
| Mcw (Mass of the cup with the water) |
272.58g |
| Mblock (Mass of the iron block) |
227.08g |
| Tsys (The max temp that the submerged block system reached) |
29.1ÁC |
| TH2O (The temp of the water before being heated) |
21.7ÁC |
| Tblock (The max temp of the iron block/boiling water system) |
96.5ÁC |
The following data reflects the data collected while working with the Aluminum Block
| Mcw (Mass of the cup with the water) |
267.76g |
| Mblock (Mass of the aluminum block) |
90.95g |
| Tsys (The max temp that the submerged block system reached) |
27.5ÁC |
| TH2O (The temp of the water before being heated) |
21.7ÁC |
| Tblock (The max temp of the aluminum block/boiling water system) |
96.2ÁC |
Analysis
The following data reflects the data analyzed while working with the iron block system
MH20 = (Mcw) - (Mcup) = 215.45g
Qr is heat released
Qa us heat absorbed
| Qr |
= |
(Mblock)(Cblock)(Tsys-Tblock) |
|
= |
(227.08g)(Cblock)(29.1-96.5) |
|
= |
(-15305.19)(Cblock) |
| Qa |
= |
(MH2O)(CH2O)(Tsys-TH2O) + (Mcup)(Cblock)(Tsys-TH2O) + (Mstirrer)(Cstirrer)(Tsys-TH2O) |
|
= |
(215.45g)(1.0)(29.1-21.7) + (57.13g)( Cblock)(29.1-21.7) + (17.06g)(0.092)(29.1-21.7) |
|
= |
(422.762)(Cblock) + (1605.9444) |
Qr + Qa = 0
(422.762)(Cblock) + (1605.9444) - (15305.19)(Cblock) = 0
Cblock = 0.108 cal/g ÁC (experimental)
Theoretical = 0.110 cal/g ÁC
Percent Error = | (Experimental - Theoretical)/(Experimental) | x100% = 2%
The following data reflects the data analyzed while working with the aluminum block system
MH20 = (Mcw) - (Mcup) = 210.63g
| Qr |
= |
(Mblock)(Cblock)(Tsys-Tblock) |
|
= |
(90.95g)(Cblock)(27.5-96.2) |
|
= |
(-6248.3)(Cblock) |
| Qa |
= |
(MH2O)(CH2O)(Tsys-TH2O) + (Mcup)(Cblock)(Tsys-TH2O) + (Mstirrer)(Cstirrer)(Tsys-TH2O) |
|
= |
(210.63g)(1.0)(27.5-21.7) + (57.13g)( Cblock)(27.5-21.7) + (17.06g)(0.092)(27.5-21.7) |
|
= |
(331.354)(Cblock) + (1230.754) |
Qr + Qa = 0
(331.354)(Cblock) + (1230.754) - (6248.3)(Cblock) = 0
Cblock = 0.208 cal/g ÁC (experimental)
Theoretical = 0.215 cal/g ÁC
Percent Error = | (Experimental - Theoretical)/(Experimental) | x100% = 3%
Discussion
The error in this lab, 2% for iron and 3% for aluminum, was fair considering the circumstances. Error could have resulted at many different points in this lap. The measuring of the boiling water as an indicator of the block's temperature is very difficult to conduct without error. The process of moving the block out of the boiling water, drying it, and inserting it into the second container results in a difference of the block's temperature. Also, the thermometer's absorption of head was not taken into consideration.
