Data:
Initial pressure (P₁)= P
Final Pressure (P₂) = 4P
Initial volume (V₁) = 20cc = 20cm³
Final volume (V₂) = ?
Using Boyle's Law, PV = constant
P₁V₁ = P₂V₂
\({ V }_{ 2 }=\frac { { P }_{ 1 } }{ { P }_{ 2 } } \times { v }_{ 1 }\)
\(=\frac { P }{ 4P } \times 20{ cm }^{ 3 }\)
V₂ = 5 cm³

Data:
Level of the liquid L₁ = 50 ml
Level of the liquid L₂ = 48.5 ml
Level of the liquid L₃ = 51.2 ml
Apparent expansion = L₃ − L₁
= 51.2 ml – 50 ml = 1.2ml
Real expansion = L₃ − L₂
= 51.2 ml – 48.5ml = 2.7ml
So, Real expansion > apparent expansion

Aim:
To measure real and apparent expansion of liquid.
Apparatus Required:
a) Round bottomed flask, a narrow glass tube with a scale, burner.
Procedure:
b) The liquid whose real and apparent expansion is to be determined is poured in a container up to a level.
c) Mark this level as L₁.
d) Now, heat the container and the liquid using a burner.
e) Initially, the container receives the thermal energy and it expands.
f) As a result, the volume of the liquid appears to have reduced.
g) Mark this reduced level of liquid as L₂.
h) On further heating, the thermal energy is supplied to the liquid through the container results in the expansion of the liquid.
i) Hence, the level of liquid rises to L₃
j) Now, the difference between the levels L₁ and L₃ is called apparent expansion. Apparent expansion = L₃ - L₁.
k) The difference between the levels L₂ and L₃ is called real expansion. Real expansion = L₃ - L₂.
Result:
The real expansion is always more than the apparent expansion.

(i) The ideal gas equation is an equation, which relates to all the properties of an ideal gas.
(ii) An ideal gas obeys Boyle's law and Charles's law and Avogadro's law.
(iii) According to Boyle's law,
PV = constant ... (1)
(iv) According to Charles's law,
V/T = constant ... (2)
(v) According to Avogadro's law,
V/n = constant ... (3)
(vi) After combining equations (1), (2), and (3), we can get the following equation.
PV/nT = constant ... (4)
The above relation is called the combined gas law
(vii) If you consider a gas which contains μ moles of the gas, the number of atoms contained will be equal to μ times the Avogadro number, N_A. i.e.,
\(n=\mu N_A\) ...... (5)
(viii) Using equation (5), equation (4) can be written as
\(PV/\mu N_AT\) = constant
(ix) The value of constant in the above equation is taken to be k_B, which is called as Boltzmann's constant. Its value is (1.381 x10^-23JK^-1). Hence, we have the following equation:
\(PV/\mu N_AT=K_B\)
\(PV=\mu N_AK_BT\)
(xi) Here, \(\mu N_AK_B=R\), which is termed as universal gas constant whose value is 8.31 J mol^-1 K^-1.
PV = RT ...... (6)
Ideal gas equation is also called as equation of state because it gives the relation between the state variables and it is used to describe the state of any gas.

(i) 0°C ice is colder than water.
(ii) This can be explained in terms of the latent heat of fusion (336 kJ) which is required to convert ice at 0°C to water at 0°C.
(iii) In simpler terms water at 0°C has higher heat content than ice at the same temperature.
(iv) Thus we conclude ice at 0°C is colder, from either of your hands.
(v) Then, you would felt more chillness on those hand, you kept ice at 0°C.