Introduction
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Introduction
States of Matter of Class 11
Matter can be classified into three categories depending upon its physical state namely solid, liquid and gaseous states. Solids have a definite volume and shape; liquids also have a definite volume but no definite shape; gases have neither a definite volume nor a definite shape.
DISTINCTION BETWEEN THREE STATES OF MATTER
|
Sl. No. |
Solids |
Liquids |
Gases |
|
1. |
Particles are very Closely packed |
Particles are loosely packed |
Particles are very loosely packed |
|
2. |
Voids are extremely small |
Voids are relatively larger |
Voids are very large |
|
3. |
Inter particle forces are large |
Inter particle forces are intermediate |
Intermediate forces are negligible |
|
4. |
Particle motion is restricted to vibratory motion. |
Particle motion is very slow |
Particle motion is very rapid and also random. |
MEASURABLE PROPERTIES OF GASES
Mass, volume, temperature are the important measurable properties of gases.
-
Mass: The mass of the gas is related to the number of moles as
n = w/M
Where n = number of moles
w = mass of gas in grams
M = molecular mass of the gas
-
Volume: Since gases occupy the entire space available to them, therefore the gas volume means the volume of the container in which the gas is enclosed.
Units of Volume:
Volume is generally expressed in litre or cm
3
or dm3 1m
3
= 103 litre
= 103 dm
3
= 106 cm
3
.
-
Pressure: The force exerted by the gas per unit area on the walls of the container is equal to its pressure.
Units of Pressure:
The pressure of a gas is expressed in atm, Pa, Nm–2, bar or,
lb/In2 (psi).
760 mm = 1 atm = 10132.5 KPa = 101325 Pa = 101325 Nm –2
760 mm of Hg = 1.01325 bar = 1013.25 milli bar = 14.7 lb/2n 2 (psi)
-
Temperature: Temperature is defined as the degree of hotness. The SI unit of temperature is Kelvin. On the Celsius scale water freezes at 0°C and boils at 100°C where as in the Kelvin scale water freezes at 273 K and boils at 373 K.
