C3.4 Gases, equilibria and ammonia Flashcards
(26 cards)
How many particles does one mole of any substance contain?
6.02 x 10^23 particles
How can you work out the number of moles of any substance?
Number of moles = mass in grams / relative atomic or formula mass
What is normal atmospheric pressure equal to?
1 atmosphere
What is stated in Avogadro’s law?
1 mole of any gas at room temperature and normal atmospheric pressure has a volume of 24dm^3
What is the room temperature used in Avogadro’s law equal to?
25 C
What do fertilisers contain that plants need to make proteins?
Soluble nitrogen compounds
Why are fertilisers added to soil?
To promote growth in plants
What does the Haber process produce?
Ammonia
What is the reaction for the production of ammonia?
Nitrogen + hydrogen ammonia
Where is nitrogen obtained from when obtaining ammonia for nitrogenous fertilisers?
The air
Where is hydrogen obtained from when obtaining ammonia for nitrogenous fertilisers?
Natural gas
What does it mean when a reaction is reversible?
It happens in both the forwards and backwards reactions
What gas is natural gas mainly composed of?
Methane
What is an advantage of artificial fertilisers?
More crops can be grown so more people can be fed
What is the disadvantage of artificial fertilisers?
They can easily be washed out of soil and into rivers and lakes, which can cause eutrophication
Why are artificial fertilisers easily washed out of soil?
They’re highly soluble
What is eutrophication?
The build up of nitrates and phosphates in water which encourages excessive plant and algae growth, leading to a depletion of light and oxygen supplies, which leads to other organisms in the water dying off
What happens during an exothermic reaction?
Heat is released because more energy is needed to make bonds than to break them
Is bond-making an exothermic or endothermic process?
Exothermic
Is bond-breaking an exothermic or endothermic process?
Endothermic
What happens during an endothermic reaction?
Heat is taken in because more energy is needed to break bonds than to make them
What is dynamic equilibrium?
When the forwards and backwards reactions happen at the same rate
What happens if a reaction in equilibrium is subject to a change in conditions?
It will adjust to cancel out the change
What conditions are used during the Haber process?
- temperature of 450 degrees
- pressure of 200 atmospheres
- presence of an iron catalyst
