Organic Chemistry Flashcards
What is methane’s formula?
Alkanes
CH4
What is ethane’s formula?
Alkanes
C2H6
What is propane’s formula?
Alkanes
C3H8
What is butane’s formula?
Alkanes
C4H10
What is Alkanes general formula?
CnH2n+2
Crude oil is a _____ fuel.
It’s formed from the remains of ______ and animals, mainly plankton, that died m______ of years ago and were buried in mud.
Over m______ of years with ______ temperature and pressure, the remains turn to ______ oil, which can be drilled up from the r_____ where it’s found.
Fossil
Plants
Millions
Millions
High
Crude
Rocks
Hydrocarbons are the simplest organic _________.
They only contain h________ and c______ atoms.
Compounds
Hydrogen
Carbon
What can fractional distillation be used to separate?
Hydrocarbon fractions.
Crude oil is a _________ of lots of different h__________, most of which are Alkanes.
The different c___________ in crude oil are separated by fractional distillation.
Mixture
Hydrocarbons
Compounds
Fractional distillation:
- Crude oil is put into the ______ of the column.
- It’s ______ up.
- Any very large hydrocarbons don’t turn into _____ and leave at the bottom of the column.
- Other molecules turn into ____ and rise up.
Bottom
Heated
Gas
Gas
Fractional distillation
- Each fraction has a different ________ point. As they rise up the column they ________ at different boiling points.
- The fractions are then __________.
- Very small molecules go all the way __ the column where it’s cool and are removed as _____.
Boiling
Condense
Removed
Up
Gases
What are the properties of hydrocarbons as you go down the fractioning column?
As you go down their: (increasing molecules size)
- Boiling points get higher
- Viscosity gets stickier
- flammability is not easy a
Combustion is another word for ________.
It happens when fuels react with ________.
Burning
Oxygen
Complete combustion is when there’s _________ oxygen available to make _____.
Enough
CO2 (carbon dioxide)
What is the complete combustion equation?
Fuel + oxygen -> water + carbon dioxide
What are the incomplete combustion equations?
Fuel + oxygen -> water + carbon monoxide
Fuel + oxygen -> water + carbon
Cracking is a t_________ decomposition reaction - breaking molecules down by h_______ them.
The first step is to heat l_____-chained hydrocarbons to v_______ them. Then the vapour is passed over a hot powdered aluminium oxide c_______.
The l____-chained split apart on the s________ of the specks of catalyst - this is catalyst cracking.
Thermal
Heating
Long
Vaporise
Catalyst
Long
Surface
You can also crack hydrocarbons if you v_______ them, mix them with s_______ and then heat them to a very h_____ temperature.
This is known as steam c________.
Vaporise
Steam
High
Cracking
Bromine water can be used to check for ________:
- When _______ bromine water is added to an _________, no reaction will happen and it will ______ bright orange.
- If it’s added to an _______ the bromine reacts with the ________ to make a colourless compound. (So the bromine water is ___________)
Alkenes
Orange
Alkane
Stay
Alkene
Alkene
Decolonised
You need to be able to _________ equations for cracking.
______ chained
hydrocarbon molecule ——> ______ alkene molecule + a______
Decane ——-> octane + ethene
Balance
Long
Shorter
Alkene
What are the 3 first alkenes?
Ethene C2H4
H H
\ /
c=c
/ \
H H
Propene C3H6
Butene C4H8
What is the general formula of an Alkene?
CnH2n
Polymerisation - diagram
H H { H H }
n \ / { | | }
c=c —> { c - c }
/ \ { | | }
H H {H H } n
Ethene Polythene (polymer)
Purity is described differently in chemistry to real life:
- Usually when you refer to a substance being pure you mean that _________ has been added to it, so it’s in its _________ state e.g pure orange juice.
- In chemistry, a pure substance is something that only contains one _________ or __________ throughout - not mixed with anything else.
Nothing
Natural
Compound
Element
What is a formulation?
A mixture that has been designed as a useful product, e.g paint, medicine.
A chemically pure substance will _____/boil at a __________ temperature.
You can _____ the purity of a sample by measuring its _______ or _______ point and c_________ it with the melting or boiling pint of the pure substance.
Melt
Specific
Test
Melting
Boiling
Comparing
Chromatography is an __________ method to separate the substances in a _________.
You can then use it to __________ the substances.
Analytical
Mixture
Identify
Chromatography:
A mobile phase - where the molecules can _____. This’s always a ________ or a ___.
A stationary phase - where molecules can’t ______. This can be a ______ or a really thick ________.
Move
Liquid
Gas
Move
Solid
Liquid
Explain how chromatography separates mixtures, in terms of solubles
Chromatography separates components in a mixture according to their solubility in the mobile phase and adsobance to the stationary phase. The components they’re more soluble in the mobile, will move through the chromatography set up faster because there are fewer interactions with the stationary phase to slow them down. These components will be absorbed first at the end part.
Chromatography
What is the Rf equation?
Rf = distance colour travelled / distance water traveller
Chromatography RP
Why is the start line drawn in pencil?
The start line is drawn in pencil, as it isn’t soluble, so won’t mix with the ink or run into the water, as in pen it would smudge/run.
How can you use chromatography to check purity?
A pure substance produces one spot on the chromatography.
An impure substance produces two or more spots.
Tests for common gases
Chlorine
Chorine bleaches damp blue litmus paper, turning it white.
Tests for common gases
Oxygen
If you put a glowing splint inside a test tube containing oxygen, the oxygen will relight the glowing splint.
Tests for common gases
Carbon dioxide
Bubbling carbon dioxide through (or shaking CO2 with) an aqueous solution of calcium hydroxide (known as lime water) causes the solution to turn cloudy.
Tests for common gases
Hydrogen
If you hold a lit splint at the open end of a test tube containing hydrogen, you’ll get a “squeaky pop”.
