Reversible Reactions and Industrial Processes Flashcards
What is an example of a reversible reaction
Unhydrated copper sulphate + water = hydrated copper sulphate
What is the equation for the reversible copper sulfate reaction
CuSO(4) + H(2)O = CuSO(4) H(2)O
How do we test for water in a copper sulfate and water reaction
Using anhydrous copper sulfate
What is a closed system
Where reactants and products can’t escape
What happens eventually with reversible reactions
They reach an equilibrium
Name the process used to make ammonia
The haber process
What chemicals are combined in the haber process to make ammonia
Hydrogen and nitrogen
What conditions are used in the haber process to stop reactions from reversing
- Temperatures of about 450 degreees
- High pressure (200 atmospheres)
- An iron catalyst speeds up reactions
What is the effect of a higher temperature with reversible reactions
To push the reaction in the direction of the smallest total number of molecules - this benefits producing ammonia, as it is a single product that has two reactants
Why do high temperatures favour the backward reactions
Because the forward reaction is exothermic, and the backward reaction endothermic. High temperatures favour endothermic reactions.
Why isn’t the haber process run at a very low temperature
Because below 400 degrees the reaction rate is too slow for profit
What yield does a moderately high temperature give in a reasonable amount of time
15%
How is ammonia removed from the cycle
It is liquified, while hydrogen and nitrogen just pass through the system repeatedly
What makes ammonia identifiable
It is the only common gas which is an alkine
What are distinctive qualities of ammonia
It has a sharp choking smell
What is the formula for an ammonium ion
NH(4)(+)
What happens when ammonium sulfate is mixed with sodium hydroxide and the mixture is heated
Ammonia is given off
Give the equation for when ammonium sulfate and sodium hydroxide are mixed and heated
NH(4) + OH = NH(3) + H(2)O
What is the last way to identify ammonia
Using hydrogen chloride gas - white smoke is made
What do most fertilisers contain
Ammonia compounds, phosphorous and potassium
What are the environmental problems with fertilisers
- The fertiliser stimulates plant growth in water
- The fastest growing plants are single celled organisms
- An algal bloom is created
- Everything in the water eventually dies
What is the most commonly used fertiliser compound
Ammonium nitrate
How is ammonium nitrate produced (equation por favor)
By neutralising ammonia solution with nitric acid
NH(3) + HNO(3) = NH(4)NO(3)
Ammonia + nitric acid = ammonium nitrate
What is the reaction to mate ammonium nitrate known as
Neutralisation reaction
What is another compound used for fertilisers
Ammonium sulfate (another neutralisation reaction)
Give the equation to make ammonium sulfate
2NH(3) + H(2)SO(4) = (NH(4))(2)SO(4)
What is sulfuric acid used for
- Making ammonium sulfate feriliser
- It’s the acid in vehicle batteries
- Making fibres, paints and dyes
- Dehydrating agent
What does the reaction of sulfuric acid with sugar demonstrate
Its power as a dehydrating agent
What is the formula for sucrose (sugar)
C(12)H(22)O(11) - The same proportions of hydrogen and oxygen as in water
What happens when sucrose reacts with concentrated sulfuric acid
The hydrogen and oxygen are removed leaving only carbon
What kind of reaction happens between sucrose and sulfuric acid
An exothermic one - the sugar basically caremalises and then turns black, and some of the water is evaporated, but gets stuck in the hardening carbon, causing the whole thing basically to grow
What is sulfuric acid made by
The contact process
What are the stages of the contact process
- The manufacture of sulfur dioxide
- The conversion of sulfur dioxide into sulfur trioxide
- The conversion of sulfur trioxide into sulfuric acid
How is sulfur dioxide made and what’s the equation
By burning sulfur in excess oxygen (irreversible)
S + O(2) = SO(2)
Excess oxygen is used because the next stage needs the rest of it
What does stage 2 of the contact process involve (equations)
Sulfur dioxide reacts with oxygen to make sulfur trioxide (reversible)
2SO(2) + O = 2SO(3)
What conditions is stage two of the contact process done under
- 450 degrees (same reasons as haber)
- Normal pressure
- Vanadium oxide as a catalyst
What does stage 3 of the contact process involve
Sulfur trioxide reacts with water to make sulfuric acid, but the reaction is uncontrollable, so the sulfur trioxide has to be dissolved first for safety reasons
What’s the equation for making oleum
H(2)SO(4) + SO(3) = 2H(2)S(2)O(7)
What’s the equation for making sulfuric acid
H(2S(2)O(7) + H(2)O = 2H(2)SO(4)
