REMEMBER
The Kelvin unit is designated with K and does not have the “°” symbol.Note: In Kelvin notation, the degree sign is omitted: 283K. The unit is the kelvin,
abbreviated as K.
Example 1
10°C = ___ K
Solution: K = 10 + 273 = 283 KExample 2
200 K = ___ °C
Solution: °C = 200 − 273 = −73°CHeat Measurements
Heat energy (or just heat) is a form of energy that transfers among particles in a
substance (or system) by means of the kinetic energy of those particles. In other
words, under kinetic theory, heat is transferred by particles bouncing into each
other.
The scales above are used to measure the degree of heat. A pail and a
thimble can both be filled with water at 100° Celsius. The water in both measures
the same degree of heat. However, the pail of water has a greater quantity of heat.
This could be easily demonstrated by the amount of ice that could be melted by
the water in these two containers. Obviously, the pail of water at 100° Celsius
will melt more ice than will a thimble full of water at the same temperature.
Therefore, the pail of water contains a greater number of calories of heat. The
calorie unit is used to measure the quantity of heat. It is defined as the amount of
heat needed to raise the temperature of 1 gram of water by 1 degree on the Celsius
scale. This is a rather small unit to measure the quantities of heat involved in most
chemical reactions. Therefore, the kilocalorie is more often used. The kilocalorie