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Flashcards in Reactions Deck (27):
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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

1

Ethanol manufacturing

By fermentation or direct hydration of ethane

2

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

3

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)

4

fermentation pros

Limited access to crude oil
Uses renewable resources
Low temperatures required
Some cases only dilute is required

5

Fermentation negatives

Produces dilute solution
Needs further processing for pure ethanol
Very slow, takes several days

6

Direct hydration pros

Very fast
Produces pure ethanol

7

Direct hydration negatives

Non-renewable resources
High temperatures and pressures- high cost

8

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

9

First 5 alkenes

Ethane
Propane
Butane
Pentane

10

Alkanes

A homologous series of compounds CnH2n+2

Burn when heated in oxygen or air

11

First five alkanes

Methane
Ethane
Propane
Butane
Pentane

12

Alkane + a lot of air and water

We're products of carbon dioxide and water

13

Alkane + insufficient air and water

Carbon monoxide formed

14

Making ammonium salts

Made when ammonia reacts with an acid
Neutralisation reaction
Indicator must be used

15

Insoluble salt

One negative ion solution + one positive ion solution

Precipitate removed through filtration

16

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

17

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

18

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)

19

Dilute acid + base

The practical technique depends on if the base is soluble or insoluble in water

20

Soluble bases

Sodium hydroxide
Potassium hydroxide

21

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

22

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

23

Dilute acids+ metal carbonates

Form salts
Carbon dioxide and water formed when they react

24

Dilute acids with bases

Bases neutralise acids to form a salt
Metal oxides/hydroxides are capable of acting as bases

25

Dilute acids with metals

Only metals above hydrogen in the reactivity series will react directly with dilute acids

26

Dilute hydrochloric acid / dilute sulfuric acid + a metal

A salt and hydrogen