Timeline VCE

Chemistry Unit 3
How can chemical processes be designed to optimise efficiency?
2017-2021

The global demand for energy and materials is increasing with world population growth. In this unit students explore energy options and the chemical production of materials with reference to efficiencies, renewability and the minimisation of their impact on the environment. Students compare and evaluate different chemical energy resources, including fossil fuels, biofuels, galvanic cells and fuel cells. They investigate the combustion of fuels, including the energy transformations involved, the use of stoichiometry to calculate the amounts of reactants and products involved in the reactions, and calculations of the amounts of energy released and their representations. Students consider the purpose, design and operating principles of galvanic cells, fuel cells and electrolytic cells. In this context they use the electrochemical series to predict and write half and overall redox equations, and apply Faraday's laws to calculate quantities in electrolytic reactions. Students analyse manufacturing processes with reference to factors that influence their reaction rates and extent. They investigate and apply the equilibrium law and Le Chatelier's principle to different reaction systems, including to predict and explain the conditions that will improve the efficiency and percentage yield of chemical processes. They use the language and conventions of chemistry including symbols, units, chemical formulas and equations to represent and explain observations and data collected from experiments, and to discuss chemical phenomena. A student practical investigation related to energy and/or food is undertaken either in Unit 3 or Unit 4, or across both Units 3 and 4, and is assessed in Unit 4, Outcome 3. The findings of the investigation are presented in a scientific poster format as outlined in the template on page 11.

 

Week
key knowledge
Topics and Lessons

Resources/Activities

(activities listed in no particular order)

 

Significant figures
- logarithms
Lesson 1 Solutions
Lesson 2 Solutions

The following revision tasks should be given as student work over the major break. The revision tasks below are in the form of small multiple choice tests with extra reading and solutions that will assist in the revision process. Revision includes,
Excess and limiting reactants,
Empirical formulae
Percentage composition,
Ionic equations,
Half equations,
Titration,
Acid-base reactions and pH,
Significant numbers.
Concentration

General questions from past exams.

2018 NHT
2016 VCE
2015 VCE
2014 VCE
2013 VCE
2012 VCE
2011
VCE
2010
VCE
2010
HSC
2009
VCE
2008
VCE
2007
VCE
2006
VCE
2005 VCE

 

AREA OF STUDY 1
What are the options for energy production?
In this area of study students focus on analysing and comparing a range of energy resources and technologies, including fossil fuels, biofuels, galvanic cells and fuel cells, with reference to the energy transformations and chemical reactions involved, energy efficiencies, environmental impacts and potential applications. Students use the specific heat capacity of water and thermochemical equations to determine the enthalpy changes and quantities of reactants and products involved in the combustion reactions of a range of renewable and non-renewable fuels. Students conduct practical investigations involving redox reactions, including the design, construction and testing of galvanic cells, and account for differences between experimental findings and predictions made by using the electrochemical series. They compare the design features, operating principles and uses of galvanic cells and fuel cells, and summarise cell processes by writing balanced equations for half and overall cell processes.

Outcome 1
On completion of this unit the student should be able to compare fuels quantitatively with reference to combustion
products and energy outputs, apply knowledge of the electrochemical series to design, construct and test galvanic
cells, and evaluate energy resources based on energy efficiency, renewability and environmental impact.

 

Obtaining energy from fuels
• the definition of a fuel, including the distinction between fossil fuels and biofuels with reference to origin and renewability (ability of a resource to be replaced by natural processes within a relatively short period of time)

• combustion of fuels as exothermic reactions with reference to the use of the joule as the SI unit of energy, energy transformations and their efficiencies and measurement of enthalpy change including symbol (ΔH) and common units (kJ mol-1, kJ g-1, MJ/tonne)

• the writing of balanced thermochemical equations, including states, for the complete and incomplete combustion of hydrocarbons, methanol and ethanol, using experimental data and data tables

• the definition of gas pressure including units, the universal gas equation and standard laboratory conditions (SLC) at 25 °C and 100 kPa

• calculations related to the combustion of fuels including use of mass-mass, mass-volume and volume-volume stoichiometry in calculations of enthalpy change (excluding solution stoichiometry) to determine heat energy released, reactant and product amounts and net volume of greenhouse gases at a given temperature and pressure (or net mass) released per MJ of energy obtained

• the use of specific heat capacity of water to determine the approximate amount of heat energy released in the combustion of a fuel.

Lesson 1 Solutions (Introduction to thermochemical equations)
Lesson 2 Solutions (Introduction of energy profile diagrams
Lesson 2a Solutions (Thermochemcial equations and Hess' Law)
Lesson 3 Solutions (Energy profile diagrams)
Lesson 4 Solutions (Stoichiometry, determining ΔH)
Lesson 5 Solutions (Determining ΔH using heat capacity of water)
Lesson 6 Solutions (Determining ΔH using heat capacity of water)
Lesson 7 Solutions (General problems on combustion reactions)
Lesson 8 Solutions (General problems)
Lesson 9 Solutions (Thermochemical equations and PV=nRT)
Lesson 10 Solutions (Thermochemical equations and PV=nRT)

Bio-fuels

Quiz 1 Solutions

Energy (enthalpy) changes during chemical reactions

Activation energy

 

Energy profiles

- endothermic reactions

- exothermic reactions

Enthalpy calculations given ΔH of two related reactions

Calculating energy release

Quiz 1 Solutions

Quiz 2 Solutions

Quiz 3 Solutions

Quiz 4 Solutions (Contains analytical chemistry questions IR and mass spec)

Quiz 5 Solutions

Quiz 6 Solutions

Quiz 7 Solutions

Quiz 8 Solutions

Quiz 9 Solutions

Quiz 10 Solutions

Quiz 11 Solutions (enthalpy energy profile and experimental technique)

Quiz 12 Solutions (enthalpy energy profile and experimental technique)

 

Past exam questions on:

- fuels
2018 VCE
2018 NHT
2017 VCE

- thermochemistry

2018 NHT
2017 VCE
2016
VCE
2015 VCE
2014
VCE
2013 VCE
2012
VCE
2011
VCE
2010
VCE
2010
HSC
2009
VCE
2009
HSC
2008
VCE
2007
VCE
2006
VCE
2005 VCE

  Fuel choices
• the comparison of fossil fuels (coal, crude oil, petroleum gas, coal seam gas) and biofuels (biogas, bioethanol, biodiesel) with reference to energy content, renewability and environmental impacts related to sourcing and combustion
• the comparison of the suitability of petrodiesel and biodiesel as transport fuels with reference to sources, chemical structures, combustion products, flow along fuel lines (implications of hygroscopic properties and impact of outside temperature on viscosity) and the environmental impacts associated with their extraction and production.

Bio-fuels
Diesel fuels
 
 

Galvanic cells as a source of energy
• redox reactions with reference to electron transfer, reduction and oxidation reactions, reducing and oxidising agents, and use of oxidation numbers to identify conjugate reducing and oxidising agents
• the writing of balanced half-equations for oxidation and reduction reactions and balanced ionic equations, including states, for overall redox reactions
• galvanic cells as primary cells and as portable or fixed chemical energy storage devices that can produce electricity (details of specific cells not required) including common design features (anode, cathode, electrolytes,
salt bridge and separation of half-cells) and chemical processes (electron and ion flows, half-equations and overall equations)
• the comparison of the energy transformations occurring in spontaneous exothermic redox reactions involving direct contact between reactants (transformation of chemical energy to heat energy) compared with those occurring when the reactants are separated in galvanic cells (transformation of chemical energy to electrical energy)
• the use of the electrochemical series in designing and constructing galvanic cells and as a tool for predicting the products of redox reactions, deducing overall equations from redox half-equations and determining maximum
cell voltage under standard conditions.

Lesson 1 Solutions (assigning oxidation numbers and recognising redox reactions)
Lesson 2 Solutions (writing balanced half equations)
Lesson 3 Solutions (Writing overall equations )
Lesson 4a Solutions (Galvanic cells)
Lesson 4b Solutions (Galvanic cells)
Lesson 4c Solutions ( Predicting if reactions will occur in a galvanic cell using Eo tables )
Lesson 5 Solutions (more galvanic cells revision)
Lesson 6 Solutions (Fuel cells)
Lesson 6a Solutions (Differences between galvanic and fuel cells and fuel cell exercises)
Lesson 7 Solutions( Revision Galvanic cells and fuel cells)
Lesson 8 Solutions( Revision redox reactions)
Lesson 9 Solutions( Revision redox reactions)
Lesson 10 Solutions ( Revision redox reactions)
Lesson 11 Solutions ( Revision galvanic cells)
Lesson 12 Solutions ( Revision fuel cells, writing half equations for different fuel cells)

Galvanic cells

Quiz 1 Solutions

Quiz 2 Solutions

Quiz 3 Solutions

Quiz 4 Solutions

Electrochemical cells
--- salt bridge
--- half equations
--- overall equations
--- potential difference
--- recharging secondary cells
--- using the electrochemical series

Past exam questions of galvanic cells

2018 VCE
2018 NHT
2017 VCE
2016
VCE
2015 VCE
2014 VCE
2013 VCE
2012
VCE
2011
VCE
2010 VCE
2010 HSC
2009 VCE
2009
HSC
2008
VCE
2006 VCE
2005 VCE

 

Fuel cells as a source of energy
• the common design features of fuel cells including use of porous electrodes for gaseous reactants to increase cell efficiency (details of specific cells not required)
• the comparison of the use of fuel cells and combustion of fuels to supply energy with reference to their energy efficiencies (qualitative), safety, fuel supply (including the storage of hydrogen), production of greenhouse gases
and applications
• the comparison of fuel cells and galvanic cells with reference to their definitions, functions, design features, energy transformations, energy efficiencies (qualitative) and applications.

Revision of fuel cells and galvanic cells Solutions

Fuel cells

Quiz 1 Solutions

Quiz 2 Solutions

Quiz 3 Solutions

Quiz 4 Solutions

Quiz 5 Solutions

Past exam questions of fuel cells

2018 VCE
2018 NHT
2017 VCE
2015
VCE
2014 VCE
2013
VCE
2012
VCE
2011
VCE
2009
VCE
2008
VCE
2006
VCE
2005
VCE

 

Area of Study 2
How can the yield of a chemical product be optimised?
In this area of study students explore the factors that increase the efficiency and percentage yield of a chemical manufacturing process while reducing the energy demand and associated costs. Students investigate how the rate of a reaction can be controlled so that it occurs at the optimum rate while avoiding unwanted side reactions and by-products. They explain reactions with reference to the collision theory including reference to Maxwell-Boltzmann distribution curves. The progression of exothermic and endothermic
reactions, including the use of a catalyst, is represented using energy profile diagrams. Students explore homogeneous equilibrium systems and apply the equilibrium law to calculate equilibrium constants and concentrations of reactants and products. They investigate Le Chatelier's principle and the effect of different changes on an equilibrium system and make predictions about the optimum conditions for the production of chemicals, taking into account rate and yield considerations. Students represent the establishment of equilibrium and the effect of changes to an equilibrium system using concentration-time graphs. Students investigate a range of electrolytic cells with reference to their basic design features and purpose, their processes in rechargeable cells, and apply Faraday's laws to calculate quantities in electrochemistry and to determine cell efficiencies.

Outcome 2
On completion of this unit the student should be able to apply rate and equilibrium principles to predict how the rate
and extent of reactions can be optimised, and explain how electrolysis is involved in the production of chemicals
and in the recharging of batteries.

 

Production of chemicals by electrolysis
• electrolysis of molten liquids and aqueous solutions using different electrodes
• the general operating principles of commercial electrolytic cells, including basic structural features and selection of suitable electrolyte (molten or aqueous) and electrode (inert or reactive) materials to obtain desired products (no specific cell is required)
• the use of the electrochemical series to explain or predict the products of an electrolysis, including identification of species that are preferentially discharged, balanced half-equations, a balanced ionic equation for the overall cell reaction, and states
• the comparison of an electrolytic cell with a galvanic cell with reference to the energy transformations involved and basic structural features and processes
• the application of stoichiometry and Faraday's Laws to determine amounts of product, current or time for a particular electrolytic process.

Lesson 1 Solutions Differences between galvanic and electrolytic cells and using the electrochemical series to predict half reactions.
Lesson 2 Solutions Aqueous vs molten electrolytes.
Lesson 3 Solutions Manipulating Faraday's laws .(Q= It, 1F = 96500)
Lesson 4 Solutions Electroplating

Electrolytic cells

--- Faraday's Law

Electrolysis in solution

Quiz 1 Solutions

Quiz 2 Solutions

Quiz 3 Solutions

Quiz 4 Solutions

Quiz 5 Solutions

Quiz 6 Solutions

Quiz 7 Solutions

Quiz 8 Solutions

Quiz 9 Solutions

Quiz 10 Solutions

Quiz 11 Solutions

2018 NHT
2017 VCE
2016
VCE
2015 VCE
2014 VCE
2013
VCE
2012
VCE
2011
VCE
2009
VCE
2009
HSC
2008
VCE
2006 VCE
2005
VCE

Rechargeable batteries
• the operation of rechargeable batteries (secondary cells) with reference to discharging as a galvanic cell and recharging as an electrolytic cell, including the redox principles (redox reactions and polarity of electrodes) and the factors affecting battery life with reference to components and temperature (no specific battery is required).

Lesson 1 Solutions

Secondary cells

Quiz 1 Solutions

Quiz 2 Solutions

Quiz 3 Solutions (secondary cells and fuel cell

 

Rate of chemical reactions
• chemical reactions with reference to collision theory, including qualitative interpretation of Maxwell-Boltzmann distribution curves
• the comparison of exothermic and endothermic reactions including their enthalpy changes and representations in energy profile diagrams
• factors affecting the rate of a chemical reaction including temperature, surface area concentration of solutions, gas pressures and presence of a catalyst
• the role of catalysts in changing the rate of chemical reactions with reference to alternative reaction pathways and their representation in energy profile diagrams.

Lesson 1 Rates of Reactions Solutions
Lesson 2 Rates of Reactions Solutions (includes PV=nRT)

Rate of reaction

Catalysts

Rates

Quiz
1 Solutions

Quiz 2 Solutions

Quiz
3 Solutions (rates and enthalpy)

Quiz 4 Solutions (rates and enthalpy)

Quiz 5 Solutions (rates and enthalpy)

Quiz 6 Solution (rates, equilibrium and enthalpy)

 

Past exam questions on rates of reaction

2018 NHT
2016 VCE
2014 VCE
2013 VCE
2012
VCE
2010
VCE
2009
VCE
2008
VCE
2007
VCE

Extent of chemical reactions
• the distinction between reversible and irreversible reactions, and between rate and extent of a reaction
• homogenous equilibria involving aqueous solutions or gases with reference to collision theory and representation by balanced chemical or thermochemical equations (including states) and by concentration-time graphs
• calculations involving equilibrium expressions and equilibrium constants (Kc only) for a closed homogeneous equilibrium system including dependence of value of equilibrium constant, and its units, on the equation used to represent the reaction and on the temperature
• Le Chatelier's principle: identification of factors that favour the yield of a chemical reaction, representation of equilibrium system changes using concentration-time graphs and applications, including competing equilibria
involved in the occurrence and treatment of carbon monoxide poisoning resulting from incomplete combustion of fuels.

Lesson 1 Solutions
Lesson 2 Equilibrium expression and Kc Solutions
Lesson 3 Changes to a system at equilibrium Solutions
Lesson 4 Visualising chemical systems at equilibrium via concentration vs time graphs and interpreting rate vs time graphs. Solutions
Lesson 5 Solution - an example of how concentration and rate are related in stressed system.

Lesson 6 Optimising yield in industry using ammonia production as an example.

Practice test on chemical equilibria. Solutions

Equilibrium
Le Chatelier's
-Summary of Le Chatelier's
Quiz 1 Solutions

Quiz 2 Solutions

Quiz 3 Solutions

Quiz 4 Solutions

Quiz 5 Solutions

Quiz 6 Solutions

Quiz 7 Solutions

Quiz 8 Solutions

Quiz 9 Solutions

Application of chemical equilibrium in industry. Provides good revision
Quiz 1 Solutions

Quiz 2 Solutions

Quiz 3 Solutions

Quiz 4 Solutions

Quiz 5 Solutions

Quiz 6 Solutions

 

 

Past exam question on chemical equilibria

2018 NHT
2017 VCE
2016
VCE
2014 VCE
2013 VCE
2012 VCE
2011
VCE
2010
VCE
2010
HSC
2009
VCE
2009 HSC
2008
VCE
2007
VCE
2006
VCE
2005
VCE

 

 

 

 

 

 

 

 

 

Revision 1 Solutions - equilibrium, electrolysis of solutions

Revision 2 Solutions - equilibrium, rates, electrolysis

Revision 3 Solutions - electrolysis

Revision 4 Solutions - equilibrium

Revision 5 Solutions - equilibrium and electrolysis

Revision Unit 3 Solutions