Chemistry Topic 7 Flashcards
What is crude oil made from?
Mixtures of hydrocarbons that are formed from the remains of animals and plants (diatoms)
What are hydrocarbons?
Compounds made up of hydrogen and carbon atoms only (group called alkanes)
What are alkanes made up of?
A chain of carbon atoms, with many hydrogen atoms bonded to it
What are the names of the 4 main alkanes and their formulas?
Methane (CH4) , Ethane (C2H6) , Propane (C3H8) , Butane (C4H10)
What is the general formula for alkanes?
CnH2n+2
How do the properties of alkanes change as the number of carbon in the molecule changes?
-boiling point increases
-the viscosity (thickness) increases
-the flammability decreases
What are the three stages of fractional distillation?
Evaporation , condensation and collection
What is catalytic convertes?
(Found in modern cars) converts some of the harmful products into less harmful products
What is cracking?
Long alkanes which are split in a thermal decomposition reaction and forms a shorter hydrocarbons
What is catalytic cracking?
A method to speed up the cracking process at lower temperatures using a catalyst
What is steam cracking?
Long alkane mixed with very high temperature and high pressure steam
What is an alkene?
When one of the molecules ends up with a double bond between 2 carbon atoms. They are unsaturated which means they have less hydrogen then alkanes
What can alkanes and alkenes be used for?
Alkanes: better fuels
Alkenes: make plastics/polymers
What is the general formula for alkenes?
CnH2n
What are polymers?
(Plastics) which are long chain molecules formed by many monomers (small molecules) bonded together
What are addition polymers?
Made when many alkenes join together
What are alcohols?
A series of organic compounds with the functional group -O-H and their names ending in -ol (methanol, ethanol, propanol, butanol)
What are alcohols used as?
Fuels, solvents and disinfectant. Alcohol dissolves well in water giving a neutral PH and it also combusts with oxygen to give CO2 and water
What are carboxylic acids?
A series of acidic compounds. They are weak acids meaning they don’t fully dissociate in water and don’t release as many ions like hydrochloric acid
PH of carboxylic acids:
The ph solution of carboxylic acids will be higher (less acidic) than for strong acids of the same concentration
What do carboxylic acids react with?
Marble chip (calcium carbonate) or magnesium but less violently
