Reactions Flashcards
Ethanol manufacturing
By fermentation or direct hydration of ethane
Reactions of ethanol
Burns when heated in air or oxygen
Can be used as a fuel
Can be dehydrated (ethanol vapour over hot aluminium oxide catalyst)
Can be used to manufacture ethane, production of polythene
Ethanol- fermentation
Dissolve sugar/starch in water
Add yeast
Leave mixture to ferment- 25-40*C
Filter of the excess yeast to obtain a dilute solution of ethanol
Direct hydration of Ethanol
Ethene and steam passed over a phosphoric acid catalyst
300*C, 60-70 atmospheres of pressure
Ethanol then condensed as a liquid
(Ethene obtained from crude oil)
fermentation pros
Limited access to crude oil
Uses renewable resources
Low temperatures required
Some cases only dilute is required
Fermentation negatives
Produces dilute solution
Needs further processing for pure ethanol
Very slow, takes several days
Direct hydration pros
Very fast
Produces pure ethanol
Direct hydration negatives
Non-renewable resources
High temperatures and pressures- high cost
Alkenes
A homologous series of compounds C2H2n
double bond between two carbons
Undergo addition reactions with halogens
C-c double bond means they can de colorise bromine
First 5 alkenes
Ethane
Propane
Butane
Pentane
Alkanes
A homologous series of compounds CnH2n+2
Burn when heated in oxygen or air
First five alkanes
Methane Ethane Propane Butane Pentane
Alkane + a lot of air and water
We’re products of carbon dioxide and water
Alkane + insufficient air and water
Carbon monoxide formed
Making ammonium salts
Made when ammonia reacts with an acid
Neutralisation reaction
Indicator must be used
Insoluble salt
One negative ion solution + one positive ion solution
Precipitate removed through filtration
Dilute acid +metal
Magnesium, iron and zinc
All are insoluble in water, do not react with water
Procedure for acid + insoluble base used
Best sign all the acid has reacted is a lack of effervescence after adding metal
Dilute acid + metal carbonate
Most metal carbonates are insoluble in water
Acid+ insoluble salt method used
A good indicator of a complete neutralisation of the acid is to wait until there are no more bubbles
Potassium and sodium carbonates (metal carbonate exception)
Soluble in water so acid+ soluble base method used
Good indicator to use is methyl orange (yellow to red)
Dilute acid + base
The practical technique depends on if the base is soluble or insoluble in water
Soluble bases
Sodium hydroxide
Potassium hydroxide
Acid + insoluble base
Heat up dilute acid in a beaker
Don’t let boil
Add insoluble base until it stops disappearing
Filter the mixture, leave in a warm place
Remove the crystals And dry them
Acid + soluble base(alkali)
Put an aqueous solution of the alkali with a suitable indicator
Add dilute acid until the indicator changes colour
Add powdered charcoal
Shake to remove the indicator changes colour
Filter to remove the charcoal
Dilute acids+ metal carbonates
Form salts
Carbon dioxide and water formed when they react
Dilute acids with bases
Bases neutralise acids to form a salt
Metal oxides/hydroxides are capable of acting as bases
Dilute acids with metals
Only metals above hydrogen in the reactivity series will react directly with dilute acids
Dilute hydrochloric acid / dilute sulfuric acid + a metal
A salt and hydrogen
