Done with Unit 3 of QCAA Chemistry and are beginning to work on Unit 4?
To help you develop an understanding of what you’ll be learning in this unit, we’ll break down all of the topics you’ll be taking on and provide you with guides on how to complete your assessments for QCAA Chemistry Unit 4.
Ready to get started? Let’s go!
What is Unit 4 in QCAA Chemistry all about?
Topic 1: Properties and Structure of Organic Materialย
Topic 2: Chemical Synthesis and Designย
QCE Chemistry Unit 4 Assessments
Study Tips
What is Unit 4 in QCAA Chemistry all about?
Unit 4 is the second of your two formative senior units for Chemistry. This means that the assessments you do for this unit (IA3 and EA) will count towards your ATAR.
The unit is split into two topics:
- properties and structure of organic materials
- chemical synthesis and design
These topics cover a variety of subtopics from equilibrium constants to electrolytic cells.ย
Topic 1: Properties and Structure of Organic Material
Structure of Organic Compoundsย
This subtopic covers:ย
- recognising that organic molecules have a hydrocarbon skeleton
- understanding the different functional groupsย
- applying IUPAC rules to name organic compoundsย
- understanding that structural isomers are compounds with the same molecular formula but different arrangement of atoms
- applying IUPAC rules to name stereoisomersย ย
- identify stereoisomers as compounds with the same structural formula but with different arrangement of atoms in space
- understanding geometrical (cis and trans) isomerism in non-cyclic alkenes
| Number of Substituents | Multiplier |
|---|---|
| 2 | Di |
| 3 | Tri |
| 4 | Tetra |
| 5 | Penta |
| Number of Carbons | Prefix for Main Chainย |
|---|---|
| 1 | Meth |
| 2 | Eth |
| 3 | Prop |
| 4 | But |
| 5 | Pent |
| 6 | Hex |
| 7 | Hept |
| 8 | Oct |
| 9 | Non |
| 10 | Dec |
IUPAC Rules
- Find and name longest continuous carbon chain (root/parent name)ย
- Identify and name groups attached to this chain (branches/substituent groups): 1C methyl, 2C ethyl, 3C propylย
- Number chain consecutively, starting at the end nearest a substituent groupย
- Designate the location of each substituent group by an appropriate number and nameย
- First write the names of the substituent groups in the order of <number dash name>
- If the same branch is present more than once, write the numbers first separated by commas and use โdi tri tetra pentaโ to describe themย
- If different branches are present, arrange the names in alphabetical order โbutyl ethyl methyl propylโ
- Last write the โroot nameโ which is the name of the longest chain as one wordย
Image sourced from Wikipedia
Physical Properties and Trendsย
This subtopic covers:ย
- recognise that organic compounds display characteristic physical properties (i.e. melting point, boiling point and solubility) that can be explained in terms of intermolecular forces
- predict and explain the trends in melting and boiling point for members of a homologous series
- understanding volatility and solubility in water of alcohols, aldehydes, ketones, carboxylic acids and halides.
| Class of Compound | Intermolecular Forces | Melting/Boiling Point | Polarity & Solubility in Water |
|---|---|---|---|
| Alkane | - dispersion forceย | Low | Low Non solubleย |
| Alcohol | - dispersion force - hydrogen bond - dipole-dipole | High | Highย Soluble |
| Aldehyde | - dispersion force - dipole-dipole | Medium | Mediumย |
| Ketone | - dispersion force - dipole-dipoleย | Medium | Medium Soluble |
| Carboxylic acidย | - dispersion force - dipole-dipole - hydrogen bond | Medium/Highย | Medium/High Soluble |
| Ester | - dispersion force - dipole-dipole | Medium | Medium |
| Amide | - dispersion force - dipole-dipole - hydrogen bond | Medium/High | Medium/High |
| Amine | - dispersion force - hydrogen bond | High | High Soluble |
| Nitrile | - dispersion force - hydrogen bond | High | High Soluble |
Organic Reactions and Reaction Pathwaysย
This subtopic covers:ย
- understanding that each class of organic compound displays characteristic chemical properties and undergoes specific reactions based on the functional group present
- saturated vs unsaturated compounds and their bonds and reactionsย
- identifying and naming the primary, secondary and tertiary carbon atoms in halogenoalkanes and alcohols
- understanding oxidation, reduction, substitution, addition, condensation and elimination reactions and relevant examples of eachย
- distinguishing between alkenes vs alkanes and primary vs secondary vs tertiary alcoholsย
- deducing reaction pathways, given the starting materials and the product
Organic Materials: Structure and Functionย
This subtopic covers:ย
- using primary, secondary and tertiary structures of organic materials to explain properties including strength, density and biodegradability
- understanding the primary, secondary, tertiary and quaternary structures of proteinsย
- structure and functions of biological catalystsย
- ฮฑ-glucose vs ฮฒ-glucoseย ย
- structural properties of starch vs cellulose
- understanding the structure and properties of triglyceridesย
- saturated vs unsaturated fatty acidsย
- understanding the process of saponificationย
- understanding how the structural features of polymers affect their propertiesย
- syntactic vs isotactic vs atactic polymersย
Image sourced from Khan Academy
Image sourced from Research Gate
Image sourced from TLAMJSย
| Amylose | - Has few glucose units per polymer and is unbranchedย - Hydrogen bonding forms between sugar units further away gains amylose final shape a coil - Soluble in waterย |
| Amylopectin | - Has large number of glucose units per polymer bonded by ฮฑ1-4 glycosidic bondsย - It is branched by forming ฮฑ1-6 glycosidic - Because of its larger size, amylopectin does not dissolve in water and is the water insoluble part of the starchย - Hydrogen bonding formed between sugar unitsย |
| Cellulose | - Monomer is a ฮฒ- glucose which forms ฮฒ1-4 glycosidic bonds - They form hydrogen bonding with glucose units forms different polymer chains |
Analytical Techniquesย
This subtopic covers:ย
- understanding how proteins can be analysed by chromatography and electrophoresis
Topic 2: Chemical Synthesis and Designย
Chemical Synthesisย
This subtopic covers:ย
- understanding the roles of reagents and reaction conditions in chemical synthesis processes including the Haber process, the contact process and the production of biodieselย
- understanding how fuels can be synthesised from a range of chemical reactionsย
- understanding the role of enzymes in chemical synthesis processes including fermentation to produce ethanol and lipase-catalysed transesterification to produce biodieselย
- describing the production of ethanol from fermentation and the hydration of ethene and the transesterification of triglycerides to produce biodiesel
- understanding the operation of a hydrogen fuel cell under acidic and alkaline conditions
- calculating the yield of chemical synthesis reactionsย
Green Chemistryย
This subtopic covers:ย
- understanding purpose of the green chemistry principlesย
- understanding that higher atom economy correlates with a โgreenerโ process
- calculating atom economy to draw conclusions about chemical synthesis processesย
Image sourced from Compound Interest
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Macromolecules: Polymers, Proteins and Carbohydratesย
This subtopic covers:ย
- understanding how addition polymers can be produced from their monomers (e.g. including polyethene, polypropene and polytetrafluorethene)
- understanding how condensation polymers can be produced from their monomers (e.g. polypeptides, polysaccharides and polyesters)
- understanding the advantages and disadvantages of polymer use (e.g. strength, density, lack of reactivity, use of natural resources and biodegradability)
- understanding that polypeptides (proteins) are formed when amino acid monomers are joined by peptide bonds and that that polysaccharides are formed when monosaccharides monomers are joined by glycosidic bonds
- understanding the condensation reaction of monosaccharides to form disaccharides and polysaccharidesย
Image sourced from Syracuse Chemistry of Artifacts Project
Image sourced from Khan Academy
Image sourced from Lumen
Molecular Manufacturingย
This subtopic covers:ย
- understanding that molecular manufacturing processes involve the positioning of molecules to facilitate a specific chemical reaction and the potential to produce specialised products
Also studying Unit 4 of Physics? Check out our Ultimate Guide to Unit 4 Physics: Revolutions in Modern Physics
QCAA Chemistry Unit 4 Assessments
Get ahead in your Unit 4 assessments by understanding where you sit in your cohort compared to your peers with our QCE Cohort Comparison tool!
#1: IA3 – Research Investigation
IA3 is the research investigation. It will assess your ability to create a scientific essay that evaluates a given claim. It constitutes 20% of your overall grade. To find out how to write your research investigation, see The Ultimate Guide to Conducting a QCAA Chemistry Research Investigation So You Can Maximise Marks.
#2: EA – External Assessment
It is an exam that consists of both Unit 3 and 4 content and constitutes 50% of your overall grade. To find out how to best prepare for the external assessment, see How to Ace Your External Assessment for QCAA Chemistry.
For practice questions, see:
Tips for Studyย
#1: Create a revision table like the one below using the syllabus dot points to guide youย
Learn more about taking effective study notes for Chemistry!
#2: Make it visual!
Use diagrams, flowcharts and other visual forms of displaying information where you can when making your notes โ this will help to make things more easy to memorise.
#3: Incorporate examples
Include examples of each concept you learn about. For example, if you’re learning about buffer solutions, make sure to include examples of a few relevant buffer solutions!
#4: Time management is essential
The syllabus has a guide on how much time should be spent on each subtopic.
While this guide is technically for teachers and their lesson planning, you as a student can also use it to help guide your study (i.e. to figure out which topics may be more important and therefore require more study time).ย
Check out also our guide on how to ace Unit 4 of Maths Methods: Further Functions and Statistics!
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