Sec physical chemistry

Published by admin on

Any thing that has mass and takes up space
Is the name scientists have given to everything that you can touch or see or feel
The study of matter and the change it undergoes
Refers to the parts or component of a sample of matter and their relative proportions.
Any characteristic that can be used to describe or identify matter
We classify matter
1) by physical state as a solid ,liquid,or gas
2) by its chemical constitution as an element ,compound,or mixture
There are 3 different physical states of matter
Solid : particles close together and organized
Liquid: particles are close together but disorganized
Gas: particles far apart and disorganized
Definite shap and volume
Particles close together , fixed
Particles move very slowly ( vibrate)
Strong intermolecular forces
Indefinite shape definite volume
Take the shape of container
Particles are close together, but mobile
Particles move slowly
Weaker intermolecular forces
Indefinite shape and volume
Take the shape and volume of container
Particles are far apart and move fast
Weakest intermolecular forces
Is a homogenous mixture of two or more substances whose relative amounts can vary within certain limits
The constituent of a solution : solute and solvent
The solute is are the substance present in the smaller amounts
The solvent is the substance present in the larger amount
Gas – Gas
Air (O in N)
Liquid -Gas
Water that dissolves in air to form Humidity
Solid -Gas
Liquid -liquid
Wine (ethanol in water)
Vinegar( acetic acid in water)
Solid -liquid
(Salt in water),(table sugar in water)
Gas – solid
Adsorption of gases eg. charcoal filter (poisonous gases in carbon), H adsorbed on pallidium
Liquid solid
Dental amalgum for filing ( liquid mercury in solid sliver)
Solid -solid
Alloys (Ag in Au) , steel ( carbon in iron)
Molecular weight
The sum of the atomic weight ( mass) of the elements in a compound
What’s the molecular weight of methane CH4?
There’s one carbon atom and 4 hydrogen atoms. The atomic weight of carbon is 12 and the atomic weight of hydrogen is 1 Adding them up we have 12+(4*1)=16
One mole can be viewed as a packet of atoms or molecules (6.02*10 to the power 23 atoms or molecules; this number is known as Avogadros constant).
Molar volume
It was found that one mole of any gas occupies a volume of 22.4 liters at standard temperature and pressure (STP)
Molar volume of a gas (at STP= 0c and 1bar)
The quantity 22.4L
In case of normal temperature And pressure
NTP= 20c and 1 bar) the molar volume equals 24 liters
Categories: Physical Chemistry