Introduction to Chemistry

Question 1

Define empirical formula

Answer 1

Simplest whole number ratio of atoms in a molecule

Question 2

Define molecular formula

Answer 2

Gives the actual number of atoms of different elements in a molecule

Question 3

Define displayed formula

Answer 3

Shows every atom and every bond in a molecule

Question 4

Define structural formula

Answer 4

Shows arrangement of atoms in a molecule without showing every bond

Question 5

Define skeletal formula

Answer 5

Uses lines to represent bonds and each vertex represents carbon atoms

Question 6

Define structural isomerism

Answer 6

When molecules have the same molecular formula but different structures

Question 7

What is positional isomerism?

Answer 7

Same molecular formula but different position of functional group attached to the main chain

Question 8

What is functional group isomerism?

Answer 8

Same molecular formula but have a different functional group due to a different arrangement of atoms

Question 9

What is chain isomerism?

Answer 9

Same molecular formula but hydrocarbon chains are organised differently e.g. branched chains

Question 10

Define stereoisomerism

Answer 10

Molecules have the same structural and molecular formula, but have a different spatial arrangement of atoms

Question 11

What is E-Z isomerism and how are the E and Z isomers decided?

Answer 11

• E-Z isomerism is caused by the limited rotation about C=C double bonds
• If the two substituents with the highest molecular mass are on the same side of the double bond, it is the Z (zusammen) isomer
• If they are on different sides, it is the E (entgegen) isomer

Question 12

Give the suffixes for:

a) No double bonds
b) At least one double bond
c) An alcohol
d) An aldehyde
e) A ketone
f) A carboxylic acid

Answer 12

a) No double bonds -ane
b) At least one double bond -ene
c) An alcohol -ol
d) An aldehyde -al
e) A ketone -one
f) A carboxylic acid -oic acid

Question 13

Give the prefixes for:

a) CH3 group
b) C2H5 group
c) C3H7 group
d) C4H9 group
e) Cl group
f) Br group
g) I group

Answer 13

a) CH3 group methyl-
b) C2H5 group ethyl-
c) C3H7 group propyl-
d) C4H9 group butyl-
e) Cl group chloro-
f) Br group bromo-
g) I group iodo-

Question 14

Define organic chemistry

Answer 14

Study of compounds containing carbon

Question 15

Define hydrocarbon

Answer 15

Molecule containing hydrogen and carbon only

Question 16

Define homologous series

Answer 16

Family of compounds with the same general formula and similar chemical properties but a different carbon chain length

Question 17

Define halogenoalkanes

Answer 17

Compounds where one or more hydrogen atoms in an alkane have been replaced by halogen atoms