Gases, equilibria and ammonia Flashcards
describe avogadros law
Equal volumes of gases contain an equal number of particles, if they are at the same temperature and pressure.
what is the molar volume of gas
One mole of any gas occupies 24 dm3. This volume is called the molar volume of the gas.
how are nitrogenous fertilisers manufactured
nitrogenous fertilisers are made from ammonia. ammonia is made from nitrogen and hydrogen is the haber process.
> nitrogen is extracted from the air
> hydrogen is made from natural gas this is mostly methane
explain nitrogenous fertilisers and what they contain
They contain nitrogen compounds, they replace the soil minerals used by plants as they grow. Fertilisers promote plant growth, increasing crop yields for farmers
describe the environmental consequences of the over-use of fertilisers
Can be washed out of the soil and into rivers and lakes when it rains. The extra minerals cause water plants to grow quickly. They cover the surface and stop light getting in. Plants underneath die and are decomposed by bacteria. These use up the oxygen in the water, causing fish to die
what is a reversible chemical reation
Reaction can go in both directions. Reaction from left to right is a forward reaction. And from right to left is a backward reaction
use a reversible reaction for the haber process
Nitrogen + hydrogen >< ammonia
describe the concept of equilibrium and dynamic equilibrium
at equilibrium, the rate of the forward reaction and the rate of the backward reaction are the same. the concentrations of all the substances involved stay constant. it is called a dynamic equilibrium because both reactions are still happening
Explain how the position of a dynamic equilibrium is
affected
temperature and pressure
how does temperature affect the position of a dynamic equilibrium
if you raise the temp, the endothermic reaction will be favoured to use up extra heat. if you reduce the temp, the exothermic reaction will be favoured to give out more heat.
how does pressure affect the position of a dynamic equilibrium
if you raise the pressure it will favour the reaction which produces less volume. if you lower the pressure it will favour the reaction which produces more volume.
what is a catalyst
A substance that speeds up the rate of reaction without being used up.
what does a catalyst do in a reversible reaction
In a reversible reaction, a catalyst increases the rate of both the forward reaction and the backward reaction by the same amount. This means that a catalyst does not change the position of equilibrium, but it does reduce the time needed to reach equilibrium. Catalysts are important for reducing coats in industrial processes
what is the haber process
The haber process is an industrial process for manufacturing ammonia. Conditions needed for the haber process are usually: an iron catalyst, a high pressure and a temperature of about 450
why are high conditions needed for the haber process
high pressure to give the best % of yield, without making plant too expensive to build. high temperature to get a faster rate of reaction. 450 degrees to get a acceptable yield in a acceptable time.
