3.3.1 Intro To Organic Chemsitry

Question 1

What is the IUPAC system for naming organic compounds?

Answer 1

A systematic method for naming organic compounds based on the longest carbon chain, functional groups, and position numbers.

Question 2

What are the different types of formulae used to represent organic molecules? • What are the different ways to represent organic molecules?
• Displayed formula
• Structural formula
• Skeletal formula
• General formula
• Molecular formula
• Empirical formula

Answer 2

Displayed formula – Shows all atoms and bonds.
• Structural formula – Shows atoms in sequence without all bonds.
• Skeletal formula – Shows bonds and functional groups but omits hydrogen atoms on carbon chains.
• General formula – The algebraic formula of a homologous series (e.g., alkanes: CₙH₂ₙ₊₂).
• Molecular formula – Shows the actual number of atoms in a molecule (e.g., C₂H₆).
• Empirical formula – The simplest whole number ratio of atoms (e.g., CH₃).

Question 3

How do you name branched alkanes?

Answer 3

Identify the longest carbon chain, number it to give substituents the lowest possible numbers, and list substituents in alphabetical order (e.g., 2-methylpentane).

Question 4

What is a homologous series?

Answer 4

A family of organic compounds with the same general formula, similar chemical properties, and a gradual change in physical properties.

Question 5

What is a functional group?

Answer 5

A specific group of atoms within a molecule responsible for its characteristic chemical reactions.

Question 6

Alkane

Answer 6

CₙH₂ₙ₊₂

Question 7

Alkene

Answer 7

CnH2n

Question 8

Alcohol

Answer 8

OH
-ol

Question 9

Aldehyde

Answer 9

-CHO
Double bond oxygen end of carbon
-al

Question 10

Ketone

Answer 10

Ketone (-CO-)
Double bond oxygen not at the end of carbon
-one

Question 11

Carboxyl acid

Answer 11

Double bond oxygen
and OH

-COOH

Question 12

Ester

Answer 12

(-COO-)

Question 13

Haloalkane

Answer 13

-X, where X = F, Cl, Br, I

Question 14

IUPAC RULES

Answer 14

1. Find the longest carbon chain and use its name as the base (e.g., methane, ethane, propane).
   
   2. Number the chain starting from the end closest to the functional group or substituent to give them the lowest numbers.
   3. Identify and name the functional group (e.g., -OH for alcohol, -CHO for aldehyde).
   4. Identify substituents (e.g., -CH₃ for methyl, -Cl for chloro) and number their positions.
   5. Combine the parts: List substituents alphabetically with their positions, followed by the parent chain name.

Question 15

characteristics of compounds in the same functional group

Answer 15

Compounds in the same series react similarly because they share the same functional group

undergo the same types of chemical reactions due to the presence of the same functional group.

Successive members of the series differ by one -CH₂- group (e.g., methane (CH₄), ethane (C₂H₆), propane (C₃H₈)).

Question 16

ethane
propane
butane

Answer 16

2
3
4

Question 17

What is isomerism?

Answer 17

The existence of two or more compounds with the same molecular formula but different structures or spatial arrangements

Question 18

What are the three types of structural isomerism?

Answer 18

Chain isomerism
Position isomers
Functional group isomerism

A structural isomer is a compound with the same molecular formula as another but a different arrangement of atoms and bonds.

Question 19

Chain isomerism
Position isomers
Functional group isomerism

Answer 19

Chain isomerism – Different arrangements of the carbon chain (e.g., pentane vs. 2-methylbutane).

Position isomerism – Same functional group in different positions (e.g., 1-bromopropane vs. 2-bromopropane).

Functional group isomerism – Different functional groups but same molecular formula

Both compounds have the same molecular formula (C₄H₈O), but one contains an aldehyde functional group, and the other contains an alcohol functional group,

Question 20

What is stereoisomerism?

Answer 20

Isomers with the same structural formula but different spatial (postion space etc ) arrangements of atoms.

Question 21

What is E/Z isomerism?

Answer 21

A type of stereoisomerism in alkenes due to restricted rotation around the C=C bond, where priority groups are on the same (Z) or opposite (E) sides.

Question 22

What is a reaction mechanism?

Answer 22

A step-by-step sequence of bond-breaking and bond-forming events in a chemical reaction.

Question 23

What is a free radical?

Answer 23

A highly reactive species with an unpaired electron, often formed in reactions involving UV light.

Question 24

CIP RULES

Answer 24

Higher atomic number = higher priority for atoms directly attached.

If two groups are the same, look at the next atom in the chain to decide priority.

For double bonds, treat them as if the atom is bonded to two extra atoms.

R/S configuration: Arrange the groups, and if the priority order is clockwise, it’s R; counterclockwise is S.

E/Z isomerism:
E: High-priority groups are opposite sides.

Z: High-priority groups are on the same side.

Question 25

What is the difference between empirical and molecular formulas?

Answer 25

Empirical formula – Simplest whole number ratio of atoms. Molecular formula – Actual number of atoms in a molecule.

Question 26

How do you calculate the molecular formula from the empirical formula?

Answer 26

1. Calculate the empirical formula mass. 2. Divide the molar mass by the empirical formula mass. 3. Multiply the empirical formula by this ratio.

Question 27

How do you determine the empirical formula of a compound?

Answer 27

Find the moles of each element from % or mass. Divide each by the smallest mole value. If needed, multiply to get whole numbers.

Question 28

How do you calculate percentage composition?

Answer 28

% Element = (Mass of element in formula / Molar mass of compound) × 100