All Students Notes

Question 3.5: Explains the derivation of absolute zero from the original definition of Charles's law. Also give graphical explanation.  Answer: The quantitative definition of Charles's law may be given as follows. "At constant pressure, the volume of a given mass of a gas increases or decrease by 1/273 of original volume at 0 ο C for every 10 ο C rise or fall in temperature respectively".   Explanation: Suppose the original volume of the gas is 546 cm 3 at 0 ο C . For each 1 ο C rise in temperature volume of the gas increase by 546 x1/273 = 2 cm 3 . When the temperature is raised by 273, the volume of the gas becomes doubled i.e 1092  cm 3 . On the other hand, if the temperature is lowered to -273 ο C or more correctly -273.15 ο C , the volume of the gas is reduced to zero. This temperature is called 0K or absolute zero . The scale on which -273.15 ο C is taken as zero is called Kelvin scale or absolute scale. The temperature measured on this scal...

Question:  How will you verify the law experimentally? Give graphical explanation of the law? Answer:     Explanation.             The law can be verified by a simple experiment as shown in figure below. Figure:   Verification of Boyle's Law It consists of a cylinder fitted with a piston and a manometer. One dm 3 of a gas at 2 atm and 25 ο C is enclosed in the cylinder. When the pressure is doubled (4 atm), the is reduced to ½ dm 3.   When the pressure is increased 3 times (6 atm), volume of the gas   the volume of the gas is reduced to 1/3 dm 3 . Hence ,                P I V I   = 2 atm x 1 dm 3      = 2 atm. dm 3                             P 2...