Summary Calorimetry Short Notes

Calorimetry
(A ) HEAT
 Internal Energy- The sum of potential energy and kinetic energy
of a molecule.
 Thermal Energy- The total internal energy of all the molecules of
a substance.
 Heat- Form of energy that flows from a hot body to a cold body
when they are kept in contact.
 Calorimetry- The measurement of the quantity of heat.
 S.I Unit of heat is joule (J).
 1 calorie (or 1 cal) = 4.186 J or nearly 4.2 J
(B ) TEMPERATURE
 Temperature- It is the parameter which tells the thermal state
of a body. It determines the direction of flow of heat when two
bodies at different temp. are placed in contact.
 S.I Unit is kelvin (K).
 T K = 273 (precisely 273.15) + t °C
 Δt °C = ΔT K
(C ) FACTORS AFFECTING THE QUANTITY OF HEAT
ABSORBED BY TO INCREASE THE TEMP. OF A BODY
 The mass of the body- Q ∝ m
 The increase in temperature- Q ∝ Δt

,  The material of the body- Objects of the same mass but
different substances absorb different amounts of heat energy
to raise their temperatures by the same amount.
 Q = c m Δt *c = specific heat capacity
(E )THERMAL (OR HEAT) CAPACITY
 Thermal (or heat) Capacity- It is the amount of heat energy
required to raise its temp. by 1 °C.
𝑄
 𝐶′ =
∆𝑡
 𝐶′ = 𝑐 × 𝑚
 S.I Unit of heat capacity- joule per kelvin (J K-1)
 NOTE- If the heat capacity of an object is 30 J K-1 , it means
that 30 J heat energy is required to raise its temp. by 1 K.
(F )SPECIFIC HEAT CAPACITY
 Specific heat capacity- The heat capacity required to raise the
temp. of unit mass of a substance by 1 K.
𝐶′
𝑐=
𝑚
𝑄
𝑐=
𝑚 × ∆𝑡
 S.I Unit is joule per kilogram per kelvin (J kg-1 K-1)
 1 𝑐𝑎𝑙 𝑔−1 ℃−1 = 4.2 × 103 𝐽 𝑘𝑔−1 𝐾 −1
 NOTE- If the heat capacity of an object is 30 J kg-1 K-1, it
means that heat energy is required to raise the temp. of 1 kg of
that substance by 1 K is 30 J.