Cooling and heating system involves the collection and dissipation of heat appropriately. Heat gradient is important for heat transfer between systems because heat travels from the warmer system to the cooler system. The right medium for heat transfer is also important for this exchange – A good conductor of heat is required.
Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly corrosive. It is used to make most fluorine-containing compounds; examples include the commonly used pharmaceutical antidepressant medication fluoxetine (Prozac) and the material PTFE (Teflon).
Dry air is a mixture of nitrogen, oxygen, carbon dioxide etc.
air is a mixture of gases 78% nitrogen an 21% oxygen and other components.