Heat Changes Involving Calories:
In a simple calorimeter all the heat released
from a chemical reaction goes into a measured quantity of water or
solution. It takes one calorie of heat to raise the temperature of 1 g of
water (or solution) one degree Celsius.
(1 g water = 1 cm3 H2O
= 1 mL H2O).
Example:
Calculate the heat released per gram of a
substance if 10 g of it changed the temperature of 150 mL of water from 20.0oC
to 25.0oC.
Solution:
150 g H2O x 5.00 oC (temperature
change) x 1 cal / 1 g x 1oC =
750 calories released
750 cal = 75 cal
10 gram 1 gram
Specific Heat Values - Joules
| Specific Heat |
J / g oC |
| Water (liquid) |
4.18 |
| Water (gas) |
1.87 |
| Water (solid) |
2.077 |
| Ethanol, C2H5OH(l) |
2.438 |
| Methane, CH4(g) |
2.200 |
| Isooctane, C8H18(l) |
2.093 |
| Aluminum, Al(s) |
0.897 |
| Table salt, NaCl(s) |
0.865 |
| Graphite, C(s) |
0.714 |
| Iron, Fe(s) |
0.449 |
| Silver, Ag(s) |
0.235 |
| Mercury, Hg(l) |
0.139 |
| Tungsten, W |
0.132 |
| Lead, Pb(s) |
0.129 |
| Gold, Au(s) |
0.129 |
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