BEHAVIOUR OF
GASES.
CHAPTER – 18.
THREE STATES OF MATTER.
1. SOLID.
2. LIQUID.
3.GAS.
NO DEFINITE SHAPE / VOLUME.
MAIN FEATURES OF GASES.
1.HIGHLY COMPRESSIBLE.
2. EXERT PRESSURE EQUALLY IN ALL
DIRECTIONS.
3. MIX EVENLY IN ALL PROPORTIONS.
4. LEAST DENSE THAN OTHER STATES
OF MATTER.
MAGIC BALLON.
FOR FIXED MASS OF GAS AT CONSTANT
PRESSURE ,THE VOLUME EXPANDS OR
CONTRACTS AS THE TEMP.. VARIES.
CHARLES
GAY LUSSAC
“UNDER CONSTANT PRESSURE
DEGREE RISE IN TEMP.., THE
VOLUME OF THE GAS
INCREASED BY 1/273 OF THE
ORIGINAL VOLUME AT 0°C
(273K)”
* “KELVIN” IS THE SI UNIT
OF TEMPERATURE.
* TEMP.. – 273°C IS CALLED
ABSOLUTE ZERO.(0K)
* AT 0K ALL GASES OCCUPU
MINIMUM TEMP..
CHARLES LAW.
“ AT CONSTANT PRESSURE,
THE VOLUME OF A FIXED
MASS OF GAS IS DIRECTLY
PROPORTIONAL TO ITS
ABSOLUTE TEMP..”
V α T.
V = KT.
(WHERE “K” IS PROPORTIONALITY
CONSTANT.)
EQUATION FOR CHARLES LAW.
= K
APPLICATIONS
OF
CHARLES LAW.
1. BALLOONS POPS OUT DURING HOT
SUMMER THAN IN WINTER.
2. SODA BOTTLES STORED IN COOL &
DRY PLACES.
ROBERT BOYLE.
RELATION
B/W
VOLUME &
PRESSURE
OF GASES
WHEN
TEMP.. IS
KEPT
CONSTANT.
BOYLE’S LAW.
“ AT CONSTANT TEMPERATURE,
THE VOLUME OF A GIVEN
MASS OF DRY GAS IS
INVERSELY PROPORTIONAL TO
ITS PRESSURE.”
DIFFUSION.
• “ RANDOM MOVEMENT OF
GASEOUS MOLECULES FROM
THE REGION OF HIGHER
CONCENTRATION TO THE
REGION OF LOWER
CONCENTRATION.”
RATE OF DIFFUSION OF
A GAS.
“ RATE OF DIFFUSION OF A GAS IS
EQUAL TO THE VOLUME OF A GAS
DIFFUSING PER UNIT TIME”
“ THE RATE OF DIFFUSION
OF A GAS IS INVERSELY
PROPORTIONAL TO THE
SQUARE ROOT OF ITS
DENSITY”

Behaviour of gases