PHYSICAL CHANGES DUE TO HEAT TRANSFER
Calorimetry I: Heat Transfer and Temperature Change
The change in temperature that a substance experiences upon a transfer of heat
depends on two things: the identity and the amount of the substance present. For
example, we could transfer 200 J of heat to a gold nugget and a piece of wood of
equal mass and, even though they were infused with the same amount of thermal
energy, the temperature of the gold would rise much more than the temperature of
the wood. Also, if this heat were transferred to two nuggets of gold of unequal
mass, the temperature of the smaller nugget would rise more than that of the larger
one.
The equation that connects the amount of heat, Q, and the resulting
temperature change, ∆T, isQ = mc∆Twhere m is the mass of the sample and c is an intrinsic property of the
substance called its specific heat. Notice that positive Q is interpreted as
heat coming in (∆T is positive, so T increases), while negative Q
corresponds to heat going out (∆T is negative, so T decreases).Calorie
A calorie is defined as the
amount of energy needed
to raise the temperature of
one gram of water by one
degree of Celsius.
1 calorie ≈ 4.18 joules- Gold has a specific heat of 130 J/kg•°C, and wood has a
specific heat of 1,800 J/kg•°C. If a piece of gold and a piece of
wood, each of mass 0.1 kg, both absorb 2,340 J of heat, by how
much will their temperatures rise?