The Haber Process/ Fractional Distillation Flashcards
(27 cards)
What does the Haber process produce?
Ammonia
How is ammonia separated from unreacted H2 and N2 2 marker
H2 and N2 are cooled, then ammonia is liquefied
What is ammonia used for?
For the manufacture of fertilizers
Explain the steps of the Haber process
H2= from natural gas N2= from air. These gases are pumped into the compressor through the pipe, the gases are compressed at 200 atmospheres.
H2 and N2 are pumped into the tank containing layers of iron catalyst beds at 450C degrees. Some of the hydrogen and nitrogen react to form ammonia.
H2,N2 and product ammonia then pass into the cooling tank where the ammonia is liquified and removed into the pressurized storage vessels.
The unreacted H2 and N2 are then recycled back and start the process again.
Why does the iron speed up the process in the tank?
Because it is a catalyst
Why is a higher temp than 450 not used for the Haber process?
At a higher temp, it favours the reverse reaction, since at high temperatures it is endothermic since more heat is taken in. Causing a higher yield of reactants to be made (H2 and N2 in this case)
Why is a lower temp than 450 not used for the Haber process?
At lower temperatures, it favours the forward reaction since at lower temperatures more heat is released and so will cause a higher yield of products to be made. Which is good since more ammonia will be produced, however the rate of reaction will be very slow due to low temperatures since particles need kinetic energy to react.
What are the things limiting to how high we make the pressure and heat?
Heat: generating heat is expensive
Pressure: high pressure is dangerous due to the risk of explosion and unsafe, and expensive as well.
Why is a higher pressure than 200 not used? What happens when a higher pressure is used?
Higher pressure favours forward reaction so the system can decrease the pressure, in order to make less molecules. Higher yield of products will be made. Which is good however at high pressures it is costly and unsafe.
Why is a lower pressure than 200 atmospheres not used? what happens when it is used?
Lower pressures favour reverse reaction so that the system can produce more molecules. A higher yield of reactants being made. However at lower temperatures, which reduces frequency of collisions between particles so the rate of reaction will be slower.
What is collision theory?
A chemical reaction can only occur when the reacting particles collide with eachother with sufficient energy.
Explain how crude oil is seperated into different fractions?
Crude oil is vaporised
The vapors of hydrocarbons enter the column which has the temp gradient. ( hottest at the bottom)
The fractions
The fractions/ hydrocarbons then cool and condense ( turn into a liquid)
All these fractions have different boiling points so they condense or cool at different temperatures.
Does ethane or an ethene have a double bond? Why?
Ethene because they’re alkene
What is the difference between alkanes and Alkenes?
Alkanes are saturated.
Alkanes can be represented by the formula Cn H 2n + 2 in which n is the number of carbon atoms
Alkanes contain single bonds
Alkenes are unsaturated.
Alkenes contain double bonds.
Represented by the equation Cn H 2n
What is ammonias chemical formula?
NH3
Explain what is simple distillation and give an example-
Simple distillation- separation technique to separate the solvent from the salt solution.
Separate water from the salt solution, by using SD until only salt is present in the flask, and we have collected all the water in the beaker.
What is fractional distillation?
Separation method for separating different mixtures/ compounds.
What is crude oil? Where is it found?
It is a mixture of hydrocarbons with different chain lengths.It is unprocessed oil, very raw oil.
It is found on land or under the sea.
What does crude oil provide us?
It’s a valuable source which provides us hydrocarbons, basically providing us with a large number of organic compounds which are used as fuels.
And for the manufacture of plastics.
How can we make the hydrocarbons that we get from the crude oil useful?
We must separate them in different fractions
Why do we call them fractions?
Because it contains a mixture of hydro carbons with similar boiling points.
How do we know which hydrocarbon will go into which fraction?
The size and the length of the hydrocarbon determines which fraction it gets separated into.
What happens when you want to separate different mixtures ( methanol, propanol, ethanol) using fractional distillation, how will you collect each mixture by itself?
Mixture is heated using Bunsen burner.
The vapour moves through the column and evaporates. The column is hot at the bottom, and cool at the top.
Put a specific boiling point, (for methanol for example- 64) so methanol will evaporate and flow out and into the condenser allowing it to turn into a liquid. However if you put propanol and ethanol in methanols boiling point, The vapors condense ( turn into a liquid and drip back down into the conical flask) ensuring only methanol is being released. Since propanol and ethanol reach parts of the fractional column ( containing glass rods) which has a lower temperature than their boiling point, allowing them to cool.
Give two conditions for cracking?
High temperature
Catalyst
