Unit 14 - Equilibruim and nitrogen Flashcards
Effect of changing pressure on equilibrium
Equilibrium will shift towards the side with fewer molecules
Effect of increasing temperature on equilibrium
Equilibrium will shift towards the endothermic side
What is dynamic equilibrium
When the reversible reaction happens at the same rate in both direction. No overall effect
Dehydration of hydrated copper(II) sulphate
By heating hydrated copper(II) sulphate (blue) it removes the water. Anhydrous copper sulphate is white and can be rehydrated
Effect of heat on ammonium chloride
When heated, ammonium chloride decomposes into ammonia and hydrogen chloride. The visible effect of this reaction is that the compound becomes a gas, when the gases cool they crystallise into their original form of solid ammonium chloride
Test for ammonium (NH4+)
Add aqueous sodium hydroxide
Identify the gas evolved, if it’s ammonia then the test is positive
Simple test for ammonia gas
Turns damp red litmus paper blue
Pungent smell
Stopper of concentrated hydrochloride acid produces a white smoke
Manufacture of ammonia (Haber process)
Nitrogen (from air) and hydrogen (from natural gases or cracking of hydrocarbons). These are passed over an ion catalyst at 200 atmospheric pressure at 450 degrees. The reaction is reversible and exothermic with a yield of about 15%. This mixture is cooled and liquified to allow any unused hydrogen and nitrogen to be recirculated
Uses of ammonia
Manufacture of nitric acid
To make fertilisers
How are nitrogen oxides formed in cars
In car engines, the temperature reached is high enough to allow nitrogen and oxygen from air to react, forming nitrogen oxides
