Unit 2 Flashcards
How are insouble salts made ?
By the precipitation reaction between 2 solutions
How is a salt formed?
When the hydrogen ion is removed from an acid and replaced by a metal ion.
What is a fuel ?
A fuel is a substance that burns releasing energy
How is a fossil fuel formed (coal)
When trees died and fell into swamp land. A build up of layers over millions of years.
How is oil and gas made
The remains of sea creatures and plants died and sunk to the sea bed. Build up of layers over millions of years.
What does incomplete combustion produce
Carbon dioxide, water and carbon monoxide
Spot can also be produced
What is a homogous
A family of chemical compounds with the same general formula + similar chemical + physical properties
What is an alkanes general formula
CnH2n+2
What is the general formula for alkenes
CnH2n
What is the general formula for cycloalkanes
CnH2n
What’s the formula for methyl
CH3
What’s the formula for ethyl
C2H5
What is the test for saturation
Adding bromine water (brown) to an Alkene will make the solution decolourise rapidly
An alkane takes much longer
A hydrocarbon with no c=c is said to be
Alkanes and cycloalkanes
Saturated
A hydrocarbon with at least 1 c=c is said to be
Alkenes
Unsaturated
What is an isomer
Molecules which have the same molecular formula but have a different structural formula or
The same number of carbons and hydrogens but a different shape
What do alkenes use in Addition reactions
Hydrogen, halogens and water
Addition reactions with hydrogen is called
Hydrogenation
Addition reactions with halogens form
Dihaloalkanes
Addition reactions with water is called
Hydration
Addition reactions with water form
Alcohols
What are carbohydrates
Compounds that contain the elements carbon, hydrogen and oxygen
Do carbohydrates provide energy
Yes
What is the test for sugar
Add Benedicts and place in a hot water bath.
If sugar is present then the colour changes from blue to orange.
What is the test for starch
Adding iodine to starch produces the colour change from brown to blue/black.
What can a carbohydrate be used for
For energy or can be used to produce fuels such as alcohols.
What is the equation for fermentation
Glucose ——> ethanol + carbon dioxide
What heat is fermentation carried out at
30/40°c
What does distilling alcohol do
Removes water and increases the alcohol content
What are alcohols also known as
Alkanols
What is the general formula for alcohols
CnH2n+1OH
What is propan-2-ol used for
Hand gels and disinfectant wipes
Why are alcohols useful as fuels
They are highly flammable and burn cleanly
The smallest alcohols are what in water ?
Miscible
When carboxylate acid reacts with an alcohol what is formed
An ester
What is an alcohol
A carbon compound which contains the hydroxyl group
What does a carboxylic acid have
Functional group called the carboxyl group -COOH
What are carbonxylic acids known as
Alkanoic acids
What do carboxylic acids names end in
’-oic acid’
What is the general formula for carboxylic acids
CnH2n+1COOH
When naming carboxylic acids where is the position of the carboxyl
Always on the end
What is one of the most widely used carboxylic acids
Ethanoic acid - vinegar
What is ethanoic acid used in
Used in chemicals to treat limescale in bathrooms or inside kettles
What PH do carboxylic acids have
Less than PH7
What do carboxylic acids form when neutralising with bases
Salts
Alcohols that are _______ create carboxyl acids
Oxidised
