Calorimetry
Heat is a form of energy that is transferred from one body to another due to temperature difference.
calorie + metry
Heat + Measurement
It means measurement of heat .
***What is heat ?
Heat is a type of energy and work is also a type of energy, so what is the difference between heat and work?
Both heat and work are the modes of energy transfer in which one is the mechanical mode of energy transfer and the other is the nonmechanical mode of energy transfer.
**HEAT :- Heat is a form of energy that is transferred from one body to another due to temperature difference.
:- It is a scalar quantity.
:- It may be - ve , +ve and zero .
:- S I unit of heat is joule(J).
:- C G S unit of heat is erg .
:- 1 Joule = 10⁷ erg.
:- Dimensional formula of heat is [ML²T⁻²].
:- Practical unit of heat is calorie .
1 calorie = 4.18 Joule
1 cal = 4.2 J
We consider that mass of the body is m and temperature changes from T₁ to T₂.
Δ Q ∝ Δ T ----------(1)
Δ Q ∝ m ---------(2)
From equation (1) and (2).
Δ Q ∝ m Δ T
Δ Q = S m Δ T
here Δ Q = Heat transfer , m= mass of body
S= Specific heat , Δ T= Change in temperature.
In Calorimetry, we learn how heat is transferred from hot body to cold body and its amount and how solid, liquid and gas change their state. It means
Solid to liquid and Liquid to solid
:- solid converts to liquid at the melting point.
:- Liquid converts to solid at the freezing point.
:- Liquid convers to gas at the vaporisation points.
:- Gas converts to liquid at the condensation point.
***Specific heat or specific heat capacity(s) :- The amount of heat required to raised the temperature of unit gram mass(1g) of substance by one degree centigrade (1°c) at 1atm is known as specific heat of substance .
or
The amount of heat required per unit mass of the substance and per change in temperature is called specific heat.
:- S I unit of specific heat is joule/kg °C .
:- Dimensional formula of s is [M⁰L²T⁻²K⁻¹]
:- Unit of specific heat is calorie/g k .
The value of specific heat capacity for
:- Water is used as a coolant in automobile radiators as well as a heater in hot hot water bags because of high value of specific heat.
Q₁ The water warms up much more slowly than the land during summer bur why?
Ans : - High value of specific heat .
Q₂ In the cities located near the sea, it feel less hot on a summer days and less cold on a winter days, but why?
Ans :- High value of specific heat capacity.
Q₃ To increase the temperature of 150 g object by 30°C, 600 cal heat is required, then find the specific heat of the object.
Q₄ How many heat (in joule) is require to raised the temperature 2kg ice from -90°C to -45°C .
Q₅ How many heat is require to raised the temperature 239g steam from 130°C to 195°C
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