Dipole Induced Dipole Forces
The hydrogen bond is really a special case of dipole forces. A hydrogen bond is the attractive force between the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule. Usually the electronegative atom is oxygen, nitrogen, or fluorine, which has a partial negative charge. The hydrogen then has the partial positive charge. Hydrogen bonding is usually stronger than normal dipole forces between molecules.
At constant temperature, the pressure of a fixed amount (i.e., number of moles n) of gas varies inversely with its volume. This isknown as Boyle's law.
pV = K
p- Pressure, V-volume, K-constant.
At a constant temperature, pressure is directly proportional to the density of a fixed mass of the gas.
Charles' Law describes the direct relationship of temperature and volume of a gas. Assuming that pressure does not change, a doubling in absolute temperature of a gas causes a doubling of the volume of that gas. A drop of absolute temperature sees a proportional drop in volume. The volume of a gas increases by 1/273 of its volume at 0°C for every degree Celsius that the temperature rises
Temperature = Constant x Volume
Volume = Constant x Temperature
Volume/Temperature = Constant
Gay Lussac's Law
At constant volume, pressure of a fixed amount of a gas varies directly with the temperature.
It states that equal volumes of all gases under the same conditions of temperature and pressure contain equal number of molecules.
V = k*n
k = Avogadro number =
Ideal Gas Equation
A gas that follows Boyle's law, Charles' law and Avogadro law strictly is called an ideal gas
pV = n RT.
R is called gas constant. It is same for all gases. Therefore it is also called Universal Gas Constant and its value is = 8.314 J K-1mol-1.
Combined Gas Law
Density and Molar Mass of a Gaseous Substance
M = (d=density)
Dalton's Law of Partial Pressures
The total pressure exerted by the mixture of non-reactive gases is equal to the sum of the partial pressures of individual gases.
p1+p2+p3+......(at constant T, V) Pressure exerted by saturated water vapour is called aqueous tension. Aqueous tension of water at different temperatures.
Partial pressure in terms of mole fraction
where is mole fraction.
BEHAVIOUR OF REAL GASES: DEVIATION FROM IDEAL GAS BEHAVIOUR
A balloon is filled with hydrogen at room temperature. It will burst if pressure exceeds 0.2 bar. If at 1 bar pressure the gas occupies 2.27 L volume, upto what volume can the balloon be expanded ?
According to Boyle's Law p1V1 = p2V2
If p1 is 1 bar, V1 will be 2.27 L
If p2 = 0.2 bar, then
V2 = p1V1/ p2 = 1*2.27/0.2
⇒V = =11.35 L
Since balloon bursts at 0.2 bar pressure, the volume of balloon should be less than11.35 L.
At 25°C and 760 mm of Hg pressure a gas occupies 600 mL volume. What will be its pressure at a height where temperature is 10°C and volume of the gas is 640 mL.
P1 = 760 mm Hg, V1= 600 mL
T1 = 25 + 273 = 298 K
V2 = 640 mL and T2 = 10 + 273 = 283 K
According to Combined gas law,
Substituting the values of in the above equation,
P2 = 676.6 mm Hg
On a ship sailing in Pacific Ocean where temperature is 23.4 °C, a balloon is filled with 2 L air. What will be the volume of the balloon when the ship reaches Indian ocean, where temperature is 26.1°C ?
V1 = 2 L
T2 = (26.1 + 273) K = 299.1 K
T1 = (23.4 + 273K) = 296.4 K
From Charles law,
Substituting the values of in the above equation, we get