Unit 2 Flashcards
What is a hydrocarbon?
A compound which contains carbon atoms and hydrogen atoms only.
Give an example of a homologous series.
Alkanes
What is a homologous series?
A family of compounds which have the same general formula and similar chemical properties.
What is the formula of Alkanes?
C↓nH↓2n+2
Are alkanes soluble in water?
No. Alkanes are insoluble in water.
Give an example of an alkane and its use.
Example: Butane
Use: Camping stove
How do you distinguish an Alkane from an Alkene using only molecular formula?
ALKENE: C↓n H↓2n
ALKANE: C↓n H↓2n+2
What is the naming system?
MEPBPHHO
Meth
Eth
Prop
But
Pent
Hex
Hept
Oct
What is the molecular formula of METHANE?
CH↓4
What is the general formula of an Alkene?
C↓n H↓2n
Alkenes have a double bond. What does this mean?
It means they are UNSATURATED.
Are alkenes soluble in water?
No. Alkenes are insoluble in water.
Give an example of a chemical property.
How a substance reacts.
Give an example of a physical property.
Melting/boiling points
What will happen to an alkane/alkene/cycloalkane as the number of carbons increase?
The number of intermolecular forces increases.
This INCREASES boiling/melting point.
What is the test for unsaturation?
The test for unsaturation (a double bond) is with BROMINE solution (bromine + water).
An ALKENE (unsatured) will rapidly decline bromine solution.
In the hydrocarbon circle, which group are the only group subject to addition reactions?
Alkenes.
What is an addition reaction?
An addition reaction is a reaction involving an ALKENE in which a molecule combines with another molecule, forming one larger molecule and no other products.
What is hydrogenation?
Alkene + Hydrogen → alkane
- Requires Catalyst
What is hydration?
Alkene + water (steam) → alcohol
- Requires Catalyst
- Requires temperature of approx 300°c
Alkene + Halogen
→ Halogenoalkane
- Spontaneous reaction
State the types of alkane branches
- Carbon (CH↓3) - METHYL
- 2 Carbons (C↓2H↓5) - ETHYL
- 3 Carbons (C↓3H↓7) - PROPYL
Draw 2-methylhexane.
check notes plz
Draw 2,2-dimethylpropane
check notes plz don’t skip it IT’S IMPORTANT PLEASE
Draw 5-ethyl-3-methyloctane
please just draw it girl or ur gon fail
How to name branched alkenes?
- Count carbons in longest chain (ie. 4=but)
- Number carbons starting closest to functional group
- Assign correct number to C=C
- Assign positions to groups (one methyl group on 2)
=
2-methylbut-1-ene
What are the formula comparisons?
- Full Structural Formula (fully drawn out)
- Shortened Structural Formula (Ch↓3CH(CH↓3)CH↓3)
- Molecular Formula (C↓4H↓10)
Draw these 8 cycloalkanes:
- Cyclobutane
- Cyclopentane
- Cyclohexane
- Cycloheptane
- Cyclooctane
What are cycloalkanes?
Saturated, cyclic hydrocarbons.
What are cycloalkanes used for?
Fuel and solvents.
Are cycloalkanes soluble in water?
No. Cycloalkanes are insoluble in water.
Which formula represents cycloalkanes?
C↓nH↓2n
Define an isomer.
Isomers are compounds with the same molecular formula but different structural formula.
(eg. Cyclopropane and Propene)
What do structural isomers vary in?
- Position of Functional Group
- Branch Position
- Homologous series with the same general formula (eg. cycloalkanes to alkenes)
What is an alcohol’s functional group?
Hydroxyl Group
Which alcohols are MISCIBLE / soluble in water and why?
Methanol, Ethanol and Propanol are soluble in water because they have a smaller chain of carbons.
What is the relation between solubility and the addition of carbons?
As carbons are added, solubility DECREASES.
Give some uses of alcohols.
- Highly flammable, good fuels
- Used as solvents in skincare or cleaning
What happens as alcohols, alkanes and alkenes increase in size?
The strength of the intermolecular forxes between molecules increases.
This increases their melting and boiling points.
Which two alcohols do not have isomers?
Methanol and Ethanol
What will happen to a straight chain alcohol if you change the position of the hydroxyl group?
An isomer will be created.
What are carboxylic acids?
A homologous series which ALWAYS end in “-oic acid”.
Properties of Carboxylic Acids:
- Dissolve in water to form acidic solutions
- React with Metals to form a Salt and Hydrogen
- React with Bases to form a Salt and Water
- React with Carbonates to form a Salt, Water and Carbon Dioxide.
These are all due to the -COOH functional group.
Name the first 8 carboxylic acids.
- Methanoic Acid
- Ethanoic Acid
- Propanoic Acid
- Butanoic Acid
- Pentanoic Acid
- Hexanoic Acid
- Heptanoic Acid
- Octanoic Acid
What is the formula for Methanoic Acid?
HCOOH
What is the formula for Ethanoic Acid?
CH↓3COOH
What is the formula for Propanoic Acid?
CH↓3CH↓2COOH
What is the formula for Butanoic Acid?
CH↓3(CH↓2)↓2COOH
Uses of Carboxylic Acids in industry:
- Preservatives in Food
- Medicines
- Vinegar is used in cleaning products as it is nontoxic
As carboxylic acids increase in size (number of carbons increase), they become ____ soluble in water and have ____ melting and boiling points due to ____ intermolecular forces.
Less soluble
Higher melting and boiling points
Stronger intermolecular forces
What is the salt name for the following:
- Methanoic Acid
- Ethanoic Acid
- Propanoic Acid
- Butanoic Acid
- Methanoate
- Ethanoate
- Propanoate
- Butanoate
Hydroxylic Acid + Metal →
Salt + Hydrogen
Hydroxylic Acid + Base →
Salt + Water
Hydroxylic Acid + Carbonate →
Salt + Water + Carbon Dioxide
What is an exothermic reaction?
An exothermic reaction is a reaction which gives out energy in the form of heat or light.
Ethanol + Oxygen →
Carbon Dioxide + Water
What is an endothermic reaction?
An endothermic reaction is a reaction which takes in heat from the surroundings.
During ____, a substance reacts with oxygen to release energy.
Combustion
What is complete combustion?
Complete combustion is when a substance burns in a plentiful supply of oxygen.
Word equation for complete combustion:
Methane + Oxygen → Carbon Dioxide + Water
What is incomplete combustion?
Incomplete combustion is when hydrocarbons and alcohols don’t have enough oxygen to burn efficiently. They produce carbon monoxide, carbon (soot), and water.
Word equation for incomplete combustion:
Methane + Oxygen → Carbon Monoxide + Carbon + Water
Complete a question using E↓h = cm∆T
check notes
Can metals conduct? If so, what?
Yes. Metals can conduct thermally or electrically.
Why can metals conduct?
The structure of metallic bonding allows for delocalised electrons, which allows them to conduct electricity and heat.
How is the structure of metals described?
As a “lattice of positive metal ions, within a sea of delocalised electrons”
How is a metallic bond held together?
A metallic bond is held together by the electrostatic force of attraction between the positive metal ions and negative electrons.
Properties of Metals:
- High MP/BP due to strong metallic bonds.
- Conduct electricity due to delocalised electrons
- Conduct heat as electrons carry heat energy as kinetic energy
- Very ductile + malleable — electrons can rearrange themselves.
