Organic Chemistry

Question 1

What is a hydrocarbon?

Answer 1

A compound that contains only hydrogen and carbon atoms

Question 2

What are the ways organic compounds can be represented?

Answer 2

-Empirical formulae
-Molecular formulae
-General formulae
-Structural formulae
-Condensed structural formulae

Question 3

What is Empirical formula?

Answer 3

-Empirical formula shows the simplest whole number ratio of atoms of each element in a compound

Question 4

What is molecular formula?

Answer 4

-Molecular formula shows the actual number of atoms in a molecule. With Methane the molecular formulae is CH4 this formulae tells us that a molecule of methane has 1 atom of carbon and that one molecule of methane has 4 atoms of hydrogen in Butane the formulae is C4H10

Question 5

give an example of Molecular formula?

Question 6

What is the general formula?

Answer 6

-Molecular formula shows the actual number of atoms in a molecule. With Methane the molecular formulae is CH4 this formulae tells us that a molecule of methane has 1 atom of carbon and that one molecule of methane has 4 atoms of hydrogen in Butane the formulae is C4H10

If the number of carbon atoms is represented by ‘n’ then the number of hydrogen atoms is n multiplied by 2 + 2 more so the general formulae for the alkanes is CnH2n+2 if we know the number of carbon atoms then we can use the general formulae to work out the molecular formulae. If there was an alkane with 12 carbon atoms and if it is put into the formulae CnH2+2 12 times 2 = 24 and + 2 = 2 26 so the molecular formulae for this compound is C12H26.

Question 7

What is the displayed formula?

Answer 7

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

Question 8

What does the structual formula show?

Answer 8

-In a structural formula enough information is shows o make the structure clear but most of the actual covalent bonds are omitted -Structural formula shows how the atoms are arranged but does not show the bonds atoms need to be shown bonded to each other carbon atoms in turn for example CH3CH2CH3 would look like this

Question 9

What is the Homologous serie?

Answer 9

-A homologous series is a series of organic compounds that have the similar features and chemical properties due to them having the same functional group but each successive member has an additatiol -CH2. For example with difference between methanol and ethanol has 2 extra hydrogen and 1 extra carbon atoms and if compared with propan-1-ol it has 1 extra C and 2 extra Oxygen This is the same in each functional group all members of a homologous series have:
-The same general formula
-The same functional group
-Similar chemical properties
-Gradation in their physical properties
-The difference in the molecular formula between one member and the next is CH2

Question 10

What is the functional group?

Answer 10

-Functional group is a group of atoms bonded in a specific arrangement that influences the properties of the homologous series
-Carbon atoms can form 4 covalent bonds, hydrogen atoms form 1 covalent bond and oxygen atoms form 2 covalent bonds.
-In functional groups such as alcohols for example with propan-1-ol the molecules have 2 part they have a chain of carbon atoms bonded to hydrogen atoms this is called the hydrocarbon chain the length is different depending on the molecule. Each molecule contains a second part which is an oxygen atom covalently bonded to a hydrogen atom called the alcohol group referred to as the functional group
-Functional group is the part of a molecule which determines how it will react in this specific functional group all of molecules have a similar functional group meaning that they will all react in a similar way