Heat capacity of metals
Objective
1. To determine the heat capacity of the calorimeter by filling it with
hot water and determining the rise in temperature.
2. To determine the specific heat capacity of aluminium, iron and brass.
Introduction
Different substances require different quantities of heat to produce a given
temperature change. For example, about three and one-half times as much
heat is needed to raise the temperature of 1 kg of iron through a given
temperature interval ∆Tas is needed to raise the temperature of 1 kg of
lead by the same amount. This material behavior is characterized quan-
titatively by specific heat, which is the amount of heat necessary to
raise the temperature of 1 gram of the substance 1 degree Cel-
sius. Thus, iron has a greater specific heat than lead The specific heat
of a material is specific or characteristic for that material. As can be seen
from the definition, the specific heat of a given material can be determined
by adding a known amount of heat of a known mass of material and not-
ing the corresponding temperature change. The purpose of this experiment
is to determine the specific heats of some common metals by calorimetry
methods.
Theory
The change in temperature ∆Tof a substance is proportional to the amount
of heat ∆Qadded (or removed) from it:
∆Q∝∆T, (1)
In equation form, we may write
∆Q=C∆T. (2)
Where the constant of proportionality Cis called the heat capacity of the
substance. However the amount of heat required to change the temperature
of an object is also proportional to the mass of the object. Hence, it is
convenient to define specific heat capacity c(or simply specific heat):
c=C
m
1
