Organic Chemistry - Topic 7 (paper 2) Flashcards
What two elements are in a hydrocarbon?
hydrogen and carbon
What is an alkane?
only contains hydrogen and carbon atoms, only has single bonds
What is the molecular form of methane?
CH4
What is the molecular form of ethane?
C2H6
What is the molecular form of propane?
C3H8
What is the molecular form of butane?
C4H10
What is the general formula for alkanes?
CnH2n+2
What is another way to describe hydrocarbons with only single bonds?
saturated
As the chain length of alkanes increases do they become more or less viscous?
more viscous
As the chain length of alkanes increases do they become more or less volatile?
Less volatile
As the chain length of alkanes increases do they become more or less flammable?
Less flammable
With an increases chain length, do alkanes have higher or lower boiling points?
Higher b.p
With an increases chain length, do alkanes have higher or lower melting hpoints?
Higher m.p
What is the word equation for the complete combustion of a hydrocarbon?
hydrocarbon + oxygen –> carbon dioxide + water
Is combustion an exothermic or endothermic reaction?
Exothermic
During a combustion reaction, are carbon and hydrogen oxidized or reduced?
Oxidized
What is “crude oil”
It is a mixture of many different compounds, most are hydrocarbons
Is crude oil finite or renewable?
Finite
How was crude oil formed?
It is formed from the remains of dead plants and animals (like plankton). These organic remains were covered by mud and sand and buried in the earth. Over millions of years, the organic remains were compressed under a lot of heat and pressure/ The heat and pressure chemically changed the organic remains into crude oil.
Give three examples of a fossil fuel.
Coal, natural gas, crude oil
How does fractional distillation work?
Crude oil is a mixture of hydrocarbons with different boiling points.
Firstly, heat the crude oil to high temps so that all the compounds are evaporated from liquid to gas.
The hot gaseous hydrocarbons rise up the fractionating column (because hot air rises).
As they rise they cool down, because the top of the column is cooler than their bottom.
The hydrocarbons will condense when they become cooler than their boiling point, and the liquid hydrocarbons then collect in trays and drain out.
The longer chain hydrocarbons condense at the bottom of the fractionating column because they have higher boiling points.
Meanwhile, the shorter chain hydrocarbons condense at the top of the column because they have much lower boiling points.
Which hydrocarbons are used as fuel?
Diesel, kerosene, petrol
Is the top of the fractional column hotter or cooler than the bottom?
Cooler
What is feedstock?
Is it a raw material used to provide reactants for an industrial reaction
What is a petrochemical?
It is a substance made from crude oil, via chemical reactions
Which two functional groups are involved in forming a polyester?
carboxyl group (COOH) and alcohol (OH)
Why are hydrocarbons used as fuels?
They release a large amount of energy when combusted
Name the first 4 alcohols
Methanol, ethanol, propanol, butanol
What two conditions are usually necessary for polymerization?
High pressure and presence of a catalyst
Are alkanes saturated or unsaturated?
saturated
What process is used to separate the components of crude oil?
Fractional Distillation
What are the waste products for complete combustion?
water vapour and carbon dioxide
What is fermentation?
Anaerobic respiration of sugars by yeast cells
