Basic concepts Flashcards

1
Q

What are alkenes

What are alkanes

A

Hydrocarbons which contain a double covalent bond between two carbon atoms in the molecule

Hydrocarbons which contain a single covalent bond between each carbon atom in the molecule

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2
Q

What is the structural pattern among the alkenes

What is the structural pattern among alkanes

A

Each carbon atoms needs four bonds. However, has two bond already due to a covalent double bond between the carbon atom.

Each carbon atom needs four single covalent bonds

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3
Q

What are the first four alkenes

What are the first four alkanes

A

Methene, Ethene, propene, butene

Methane, ethane, propane, butane

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4
Q

What are some examples of functional groups

A

Carboxylic acids

Alkanes

Alcohols

Amines

Alkenes

Ketoners

Esters

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5
Q

What group is alcohol a part of?

A

The hydroxyl group

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6
Q

What is the structure of an alcohol

A

A hydrogen is covalently bonded to an oxygen which is covalently bonded to the rest of the molecule.

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7
Q

What are some examples of alcohols

A

Methanol, ethanol ,propanol, butanol

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8
Q

What are some examples of alcohols

A

Methanol, ethanol ,propanol, butanol

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9
Q

What suffix is given to the functional group carboxylic acid

A

-oic acid

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10
Q

What are the first four carboxylic acids

A

Methanoic acid , Ethanoic acid, propanoic acid, butanoic acid

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11
Q

Uses of Esters:

A

Gives molecules a sweet smell and makes them useful for perfumes and flavourings

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12
Q

Uses of Ketones:

A

Makes molecules useful as solvents

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13
Q

Uses of Amines

A

Can be useful as dues and useful in making medicines

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14
Q

Why is the displayed formula used so frequently?

A

The displayed formula provides the clearest visual structure of an organic molecule

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15
Q

Why is the structural formula used?

A

It is often used when writing equations

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16
Q

What does the empirical formula show

A

The ratio of atoms in the molecule

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17
Q

What are organic chemicals

A

Covalent molecules based on the element carbon

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18
Q

Give three examples of organic molecules (draw them out)

A

Methene, alkane, propan-1-ol

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19
Q

Describe one key feature among carbon atoms

A

They form four covalent bonds

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20
Q

Describe a key feature among oxygen atoms

A

They form two covalent bond

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21
Q

Describe one key feature among hydrogen atoms

A

They form one covalent bond

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22
Q

What is the hydrocarbon chain

A

A hydrocarbon chain is an organic molecule consisting of nothing else but carbon and hydrogen atoms arranged in a chain.

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23
Q

What group is methanol, ethanol , propan-1-ol a part of

A

The alcohol group

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24
Q

What is a functional group

A

The part of the molecules which determines how it reacts

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25
Q

What is a homologous series

A

A homologous series of organic molecules have the same functional group but each successive member has an additional -CH2

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26
Q

What would the functional group be in Chloromethane,1-chloroethane and 1-chloropropane

A

The functional group would be chlorine atom

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27
Q

What is a hydrocarbon

A

A molecule which contains only hydrogen and carbon atoms

28
Q

What is a saturated hydrocarbon

A

Hydrocarbons with single covalent bonds between the carbon atoms

29
Q

What is an unsaturated hydrocarbon

A

Any hydrocarbons with double or triple covalent bonds between the carbon atoms

30
Q

What are the first three member of the alkane homologous series

A

Methane, ethane, propane

31
Q

What are the prefix for the first ten alkane/enes

A

Meth, eth, prop, but, pent, hex, hept, oct, non, dec

32
Q

What is the rule when numbering unbranched carbon chains

A

To name the molecule you have to show the position of the double bond

This is done by choosing the end which produces the lowest possible numbers

33
Q

What is a branched chain hydrocarbon

A

A hydrocarbon molecule with a side chain (branch)

34
Q

How to identify the name of a branched hydrocarbon molecule

A

Identify the longest chain of carbon atoms

Look at the number of carbon atoms on the side chain

State the position of the side chain on the main carbon chain by numbering the carbon atom (lowest possible number)

If there are two side chain on the carbon chain both side chains will be mentioned . E.g= 3,3- or 3,5-

35
Q

What is the rule for side chains when listing organic molecules

A

Side chains are listed alphabetically

36
Q

What is the molecular formula

A

The molecular formula of a compound tells us the actual number of atoms of the elements in that compound

37
Q

How do you write the molecular formula of a compound

A

The carbon atoms should be written first then the hydrogen atoms. Any other elements are then listed alphabetically

38
Q

Disadvantages of the molecular formula

A

It does not give us any information on the structure of the molecule.( How the atoms are bonded together)

Different compounds can have the same molecular formula

39
Q

What is the empirical formula

A

The empirical formula is the simplest whole number ratio of the atoms of each element in a compound

40
Q

What is the empirical formula of Ethane (C2H6)

A

CH3

41
Q

Explain the displayed formula

A

The displayed formula shows us the relative position of each atom plus all the covalent bonds

42
Q

Disadvantages of the displayed formula

A

Does not show accurate bond angles

43
Q

Explain the structural formula

A

The structural formula shows how atoms are arranged but does not show us the bonds.

The atoms are shown to bond with each carbon atom in turn

44
Q

How can the structural formula be shortened

A

If there is a consecutive pattern among the structural formula brackets can be put around the specific carbon chain and a subscript can be placed outside the bracket to show how many times this pattern is repeated.

E.g:

CH3CH2CH2CH2CH3

CH3(CH2)3CH3

45
Q

How can you add the side chain on structural formula

A

In structural formula the methyl group is placed in brackets.

The methyl group is included straight after the parent chain it is attached to is mentioned on the structural formula.

46
Q

Explain the skeletal formula

A

It is the simplest possible way to represent the structure in an organic molecule

We do not show the carbon and hydrogen atoms. The only shown are in the functional group

The covalent bond between carbon atoms and bonds to any functional group are shown

47
Q

Explain the general formula

A

The general formula is the simplest algebraic formula for a member of a homologous series

48
Q

What is the general formula for alkanes

A

CnH2n + 2

49
Q

How can you use the general formula to find the molecular formula of an organic molecule

A

Input the amount of carbon atoms the organic molecule has and follow the general formula.

The answer will be the amount of hydrogen atoms in the organic molecule

50
Q

What is the general formula for alkenes

A

CnH2n

51
Q

What is the general formula for the chloroalkanes

A

CnH2n + 1 Cl

52
Q

What is the general formula for alcohol

A

CnH2n + 1 OH

53
Q

Why can CnH2n + 2 not be used for a general formula for alcohol

A

You need to show the functional group in the general formula

54
Q

What is a structural isomer

A

Structural isomers are molecules with the same molecular formula but different structural formulae

55
Q

What do you need to be aware of with alkenes during structural isomerism

A

Alkenes have structural isomers which are called cycloalkanes.

These are structural isomers of pentene

56
Q

What is an example of two structural isomers that have different functional groups

A

Ethanoic acid and methyl methanoate

57
Q

What are stereoisomers

A

Stereoisomers are molecules with the same structural formula but the atoms are arranged differently in space

58
Q

What condition result in alkenes to have cis/trans isomers

A

The carbon atom in the double bond must be attached to two different groups

At least one group must be the same on both carbon atoms on the double bond

59
Q

How can you differentiate between a cis / trans isomer

A

you look at the group which is the same on both sides of the double bond.

If the certain group is on the same side of the molecule it is a cis isomer whereas if it was on opposite sides it would be a trans isomer

60
Q

Draw the cis and trans isomers of but-2-ene

A
61
Q

Why does but-1-ene not have any cis / trans isomers

A

Both carbon atoms on either side of the carbon bond must be bonded to two different groups

At least one of those groups must be the same for both carbon atoms

62
Q

Why cannot the cis / trans ruling system be used for all isomers

A

Some alkenes may be bonded to more than 2 different groups on a double bond. Thus the cis / trans rule cannot be used. Thus E / Z is used.

63
Q

Why can cis-trans isomers only exits in two forms

A

Unlike single covalent bonds, double bonds has very restricted rotation and thus can only form into two isomers

64
Q

How is the E / Z naming system used for isomers

A

We start by looking at the group which is the same on the carbon atoms on either side of the double bond.

If the group is on the same side of he molecule we call this a Z isomer (cis)

If the group is on the opposite side of the molecule we call this the E isomer (trans)

65
Q

Advantages of the cis / trans system over the cis / trans system

A

The E / Z system can be used for alkenes which have more than 2 different groups on the double bond. Thus the cis / trans rule cannot be used. Therefore, E / Z is used.

66
Q

Explain how to use the CIP priority rules when using the E / Z naming tule

A

First we look at the atom attached to the carbons either side of the double bond

The element with the greatest atomic number is given the higher priority

We assign E or Z using the higher priority groups