4.1 BASIC CONCEPTS & HYDROCARBONS Flashcards
1
Q
State what functional groups are responsible for
A
- the reactions of a compound
2
Q
Define homologous series
A
- A series of organic compounds with the same functional group, similar chemical properties and each successive member differing by CH2
3
Q
Define homolytic and heterolytic fission
A
- Homolytic fission is when a covalent bond breaks equally to give each atom an electron and form two radicals
- Heterolytic fission is when a covalent bond breaks and one atom takes both electrons to form a positive and negative ion
4
Q
Describe the route of curly arrows
A
- Movement of a pair of electrons from a lone pair,bond or negative charge to an atom
5
Q
Define radical
A
- A highly reactive species with an unpaired electron
6
Q
Define electrophile
A
- An electron pair accepting species with postive/δ positive charge, attracted to areas of electron density
7
Q
Define nucleophile
A
- An electron pair donating species with negative/δ negative charge, attracted to electron deficient areas
8
Q
Define structural isomerism
A
- Compounds with the same molecular formula but different structural formula
9
Q
State the three types of structural isomerism
A
- functional group isomerism
- chain isomerism
- positional isomerism
10
Q
Define stereoisomerism
A
- Compounds with the same molecular formula and same structural formula but different arrangementof atoms in space
11
Q
State the two features required for cis/trans isomerism
A
- Unsaturated C=C bond
- Atleast two atom groups to be the same
12
Q
State the two features required for E/Z isomerism
A
- Unsaturated C=C bond that has restricted rotation
- Each carbon atom of the double bond is attached to two different atoms/atom groups
13
Q
Draw E/Z isomerism
A
14
Q
Draw cis/trans isomerism
A
15
Q
State the 4 ways of disposing polymers
A
- Use as organic feedstock
- Recycling
- Combustion
- Landfill
16
Q
State the 2 environmental polymers
A
- photodegradable
- biodegradable
17
Q
Explain the shape and bond angle of alkanes
A
- Tetrahedral
- 109.5°
- All four bonding pairs of electron regions repel equally
18
Q
3 properties of alkanes
A
- Non-polar
- MP/BP increases with carbon chainlength
- Insoluble (nonpolar)
19
Q
Draw a sigma bond and state which molecules they are present in.
A
- Present in both alkanes and alkenes
20
Q
Draw a pi bond and state which molecules they are present in.
A
- Present in alkene double bond only
21
Q
State why alkanes are unreactive
A
- High bond enthalpy
- Low polarity of the σ bonds
22
Q
A
23
Q
A
24
Q
Write the equations for the free radical substitution of ethane with chlorine
A
25
State the **2 limitations** of **free radical substitution**
- **Impurities** are formed during **termination** that are not **haloalkanes**
- **Further substitution** may occur
26
Explain the affect of **branching** on **MP/BP** for hydrocarbons
- **Boiling point increases** with **less branching** of **side groups**
- **Less branching** gives more **surface contact** between **molecules**
- More **surface contact** gives **stronger london forces** which require **more energy** to **break**
27
Write the **equation** for the **complete** and **incomplete combustion** for **alkanes** (**C3H8**)
28
State the **issue** with **carbon monoxide**
- **toxic** and **odourless** gas that **irreversible binds** to **haemoglobin**
29
Explain why **alkenes** are more **reactive** than **alkanes**
- the **bond enthalpy** of the **π** bond is less than the **bond enthaply** for the **σ** bond
30
Draw **sigma** and **pi** bonds in **alkenes**
31
Explain the shape and bond angle of **alkenes**
-**Trigonal planar**
- **120°**
- All **three bonding pairs** of **electron regions repel equally**
32
Explain why **alkenes** are **reactive**
- They have **relatively low bond enthalpy** of the **π** bond compared to **sigma** bond
- The **π** bond is **broken first**
33
State all the **addition reactions** of **alkenes** and their **conditions**
34
Write out the **hydrogenation** of **alkenes** (**ethene**)
35
Write out the **halogenation** of **alkenes** (**ethene**) with **mechanism**
36
Write out the **hydration** of **alkenes** (**ethene**)
37
Write out the **addition of hydrogen halide** of **alkenes** (**ethene**) with **mechanism**
38
Explain how the **major product** of **addition reactions** is determined
- the **hydrogen** atom of the **H-X** attaches to the **carbon** with the most **hydrogens** on it already
- because **carbocations** with more **hydrogen** atoms on are more **stable**
39
State the **benefit** of **environmental polymers**
- **Reduces** the need for **finite** resources
40
State a **danger** of **combustion** of **polymers**
- Releases **toxic HCl fumes**
