Chemistry: Important Chemical Processes

Chemistry: Important Chemical Processes

 

Diffusion:

• Spreading & mixing of one substance with the another due to the motion of particles, which continues till a uniform mixture is formed
• Mixing particles move in zigzag known as Brownian motion
• Increases with temperature, fastest in gases & slowest in solids
• Few of the examples are : Dust particles in air, Smell of perfume in air, Spread of virus on sneezing, CO2 & O2 in water, Leakage of LPG (Identified by ethyl mercaptan – a strong smelling substance)

 

Osmosis:

• Diffusion is the case of using semi permeable membrane b/w 2 mixtures
• Only solvent is allowed to pass, from higher solvent conc. to the lower
• Few of the examples are: Preserving of pickle in salt, swelling up of raisins in water, Earthworm dying when come in contact with salt

 

Dialysis:

• Same as osmosis but for transplantation of kidney in humans
• Passes solvent & blocks waste

 

Latent heat:

• To change the state of a substance from one to heat energy is required.
• Latent heat does not increase temp. of a substance but is used in overcoming force of attraction b/w particle of a substance

It’s due to loss of latent heat that ice at 0*C is more effective in cooling than water at 0*C & due to gain of latent heat that steam at 100*C causes more severe burns than water at 100*C

 

Evaporation:

• Transition of liquid to vapor at normal temperature
• Causes cooling when liquid evaporate as it draws latent heat of vaporization from the liquid
• For ex. evaporation of ether or spirit from our hand, sweating, water kept in earthen pot
• Increases with temp, large surface area, wind speed & low humidity

 

Sublimation:

• Transition of solids directly into gases without going through liquid state
• Ex: Dry ice, Camphor, Ammonium chloride, Iodine, Naphthalene, Anthracene