Hydrocarbons Flashcards
What is the functional group of Alkenes?
The carbon double bond
What are isomers?
Molecules with the same molecular formula but different arrangements of atoms
What is the bromine water test?
Bromine water has an orange-brown colour
When it is mixed with Alkenes, a chemical reaction occurs leading to colourless products.
Alkanes do not cause decolorisation so this is a good test to determine if something is an Alkane or Alkene
Why does this test work?
The double carbon bond reacts with the bromine to form a colourless product.
Therefore, the bromine is removed from the solution so it loses its colour
Alkanes don’t have a double carbon bond
What is an addition reaction?
A reaction in which reactants combine to form one larger product molecule and no other products.
How do you name the single product in addition reactions?
Add ‘di-‘ to the beginning if diatomic
It’s 1.1 if the atom e.g. bromine, is attached to one carbon atom.
If it’s attached to two, it’s 1.2 and so on
If it’s by itself, it’s 1 - (name) if it’s on the first carbon
2 - (name) if it’s on the second carbon
And so on
What is the ethanol in alcoholic drinks made from?
Sugars
What family of substances do sugars belong to?
Carbohydrates
Are these sugars soluble or insoluble?
Soluble
Why are fruit used frequently in alcoholic drinks?
Fruit contains a lot of sugars
What do seeds contain?
Starch
What needs to happen to starch before it can be used in alcoholic drinks?
Must be broken down into sugars
What must happen to the seeds before using them?
Must be germinated
What happens during this process?
Enzymes in the seeds turn the starch into sugars
What plant is commonly used in beer?
Barley seeds
What plant is commonly used in wine?
Grapes
What plant is commonly used in whiskey?
Barley seeds
What plant is used in vodka?
Wheat seeds
What is fermentation?
When plant material contains sugars (e.g. glucose) it is mixed with water and yeast at 25 degrees and turns it into ethanol and carbon dioxide
What are the conditions for fermentation?
Temperature and pH of the solution must be carefully controlled
Oxygen must be kept out of container as yeast fermentation is an example of anaerobic respiration (doesn’t require oxygen)
Why is fermentation only used on weak(er) drinks?
Fermentation produces drinks up to 15% alcohol content
Anymore, and the higher concentrations kill the yeast cells
How are higher concentrated solutions produced?
Fractional distillation
I,e, Boiling point of ethanol is 78 degrees.
The first fraction collected will contain a higher percentage of alcohol
What is the function group of alcohols?
-OH
What are the similar chemical properties of alcohols?
Produce carbon dioxide and water on complete combustion
Can be oxidised to form carboxylic Acids
React with reactive metals such as sodium, which forms hydrogen gas
What is the Core-Practical for The combustion of Alcohols?
1) Measure the mass of an alcohol burner and cap. Record the mass and the name of the alcohol.
2) Place the alcohol burner in the centre of a heat-resistant mat
3) Use a measuring cylinder to add 100cm cubed of cold water to a conical flask
4) Measure and record the initial temperature of the water and clamp the flask above the alcohol burner
5) Light the wick of burner and allow the water to heat up to 40 deg.
6) Replace the cap on burner and measure and record final temperature of the water
7) Measure the mass of alcohol burner and cap again and record the mass
8) Calculate the mass of alcohol burned to produce a 1 deg.rise in temperature.
9) Reapeat using different alcohol and fresh cold water
What are the first four carboxylic Acids?
Methanoic acid
Ethanoic acid
Propanoic acid
Butanoic acid
What are the similar chemical properties of carboxylic Acids?
They all:
- Form solutions with a pH lower than 7 (if soluble)
- React with metals to form a salt and hydrogen
- React with bases to form a salt and water
- React with carbonates to form a salt, water and carbon dioxide
How can vinegars be used to test for carbonate rocks e.g. limestone?
The ethanol acid fizzes producing carbon dioxide
How are carboxylic Acids produced?
When alcohols are oxidised
All weak Acids
What does the functional group of carboxylic Acids, form when in a solution?
Hydrogen ions
What is the functional group of carboxylic Acids?
= o
-c
\o - h
What are monomers?
A single small molecule
What is a polymer?
A long chain molecule made of many monomers
What are the two types of polymerisation ?
Addition polymerisation
Condensation polymerisation
What is addition polymerisation?
A type of polymerisation where the monomers add on to each other and no small molecules are eliminated
Process happens again and again forming a long chain
What is used to show this repeating chain?
Repeating unit
How do you name a polymer of any monomer?
Poly (monomer)
E.g. polymer of Ethene
Poly (Ethene)
Why is poly (Ethene) a synthetic polymer?
It is manufactured in a laboratory or factory
What are some naturally occurring polymers?
Proteins - polymers from amino acids
Starch - polymer from sugar
What are the properties and uses of poly(Ethene)?
Flexible, cheap, good insulator
Uses: Plastic bags, plastic bottles, cling film, polytunnels
What are the properties and uses of poly(propene)?
Flexible, does not shatter
Uses: Buckets, bowls, crates, ropes and carpets
What are the properties and uses of poly(chloroethene)?
Tough, good insulator, can be made hard or flexible
Uses: window frames, gutters, pipes, insulation for electrical wires
What are the properties and uses of PTFE : poly(tetrafluoroethene)?
Tough and slippery
Non-stick coatings on pans, kitchen utensils (non-stick), stain proofing carpets and clothes
What is condensation polymerisation?
Where monomers join together and eliminate a small molecule I.e. water (create it as a by-product)
What is the functional group for esters?
O
/
-C
\\
OHow are esters formed?
Carboxylic Acid + alcohol = ester + water
What are Ester links?
They are the two functional groups (alcohol and carboxylic acid) at the end of each of the molecules.
Must have 2 functional groups to form a long chain
Why are using monomers to make synthetic polymers a problem?
They are obtained from crude oil which is a non-renewable source.
Why is the synthetic polymers not being biodegradable a good and bad thing?
Good: Last for long time
Bad: Do not break down/rot when thrown away
How can burning plastics (synthetic polymers) be a bad thing? And good?
Burning releases energy which can be converted to electricity
However, burning emits greenhouse gases like carbon dioxide
Some even produce toxic substances when burnt
How can we prevent this?
Reuse plastic bags
Help conserve supplies of crude oil - stop making more and just reuse
Why is it difficult to recycle polymers?
Collect the waste
Sort the waste into different types of polymers - done by hand -expensive.
Dispose of waste that can’t be recycled
Clean polymers and grind them into chippings
Purify the chippings
Melt the chippings then process into new product
