Advertisements
Advertisements
Question
Give its
(i) graphical representation,
(ii) mathematical expression
(iii) significance
Advertisements
Solution
(i) Graphical representation of Charles's law
T vs V: The relationship between the volume and the temperature of a gas can be plotted on a graph. A straight line is obtained.
(ii) Mathematical expression
Let V0 be the volume of a fixed mass of a gas at 0 °C, and let V be its volume at temperature t °C at, constant pressure. then, according to Charles Law
`"V" = "V"_0 + "V"_0/273 t` (when P is constant)
`"V" = "V"_0 (1 + t/273) = "V"_0 ((273 + t)/273)` .......(1)
`"V" = "V"_0/273 "T" "where" "T" = 273 + "t"`
For a given mass of a gas,
`"V"_0/273 = "constant"`
`"V" = "k" xx "T"` (where k is constant)
(iii) Significance of Charles's Law: The volume of a given mass of a gas is directly proportional to its temperature; hence, the density decreases with temperature. This is the reason that
(a) Hot air is filled in balloons used for meteorological purposes. (b) Cable wires contract in winters and expand in summers.
APPEARS IN
RELATED QUESTIONS
Explain Charles's law on the basis of the kinetic theory of matter.
Give reasons for the following:
Mountaineers carry oxygen cylinders with them.
Choose the correct answer:
The volume-temperature relationship is given by
2 liters of gas is enclosed in a vessel at a pressure of 760 mmHg. If the temperature remains constant, calculate pressure when volume changes to 4 dm3.
2500 cm3 of hydrogen is taken at STP. The pressure of this gas is further increased by two and a half times (temperature remaining constant). What volume will hydrogen occupy now?
An LPG cylinder can withstand a pressure of 14.9 atmospheres. The pressure gauge of the cylinder indicates 12 atmospheres at 27°C. Because of a sudden fire in the building, the temperature rises. At what temperature will the cylinder explode?
State Charles's law.
A certain mass of gas occupied 850 ml at a pressure of 760 mm of Hg. On increasing the pressure it was found that the volume of the gas was 75% of its initial value. Assuming constant temperature, find the final pressure of the gas?
It is required to reduce the volume of a gas by 20% by compressing it at a constant pressure. To do so, the gas has to be cooled. If the gas attains a final temperature of 157°C, find the initial temperature of the gas.
A fixed volume of a gas occupies 760cm3 at 27°C and 70 cm of Hg. What will be its vol. at s.t.p.
