Unit 3 Chemistry
succeeding in the vce, 2017
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it is illegal to use any kind of recording device during this lecture WHAT IS A FUEL?
Fuel: A chemical substance that can react via a chemical or nuclear reaction
to produce useful energy.
The chemistry of fuels is an important area of study since:

Society is dependent on the energy gained by fuels.

It is important to be able to compare the energy content and energy efficiency of
different fuels.

The combustion of fuels has significant environmental impacts.
ENTHALPY OF COMBUSTION
Combustion reactions are energy releasing. This is because the energy content of the
products is less than the energy content of the reactants. The difference in energy between
the reactants and products is released as heat which increases the temperature of the
surroundings.
Chemical energy is stored inside every substance and results from the potential (stored)
energy and kinetic (movement) energy of the system. Examples include:
Attractions between protons and electrons.
Repulsions between nuclei.
Interactions between atoms (chemical bonds).
Potential Energy
Movement of electrons.
Vibration of nuclei.
Movement of atoms, ions and molecules.
Kinetic Energy
Note: The greater the degree of motion, the higher the kinetic energy.
The chemical energy of a substance is the sum of the potential and kinetic energies, and is
referred to as the heat content or enthalpy (H).
As different substances contain different combinations of atoms (and hence different
types/strengths of bonding), it is highly unlikely that two different substances will have the
same enthalpies. It is therefore reasonable to assume that reactions involve a change in
enthalpy (  H ) or heat content.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 1
The change in enthalpy as a system undergoes a chemical reaction is determined by
calculating the difference between the enthalpies of the products and reactants.
 H = Enthalpy of Products – Enthalpy of Reactants
 H  H Products - H Reactants
When this difference is positive (  H   ve ) , the reaction is endothermic.
When this difference is negative (  H   ve ) , the reaction is exothermic.
Enthalpy values are usually measured in units of kJ mol 1 .
If the energy of the products is less than the energy of the reactants, the reaction will be
exothermic.
The combustion of fuels is always EXOTHERMIC  energy releasing!
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 2
THERMOCHEMICAL EQUATIONS
A thermochemical equation shows the amount of energy released or absorbed (enthalpy
change) during a chemical reaction. They are a useful tool for comparing the energy
released by the combustion of fuels.
An example of a thermochemical equation is:
2C2 H 6( g )  7O2 ( g )  4CO2 ( g )  6 H 2O( g )
H  1778 kJ / mol
This equation indicates that when 2 mole of C 2 H 6 reacts with 7 mole of O 2 , 4 mole of CO2
and 6 mole of H 2O are produced. In the process, 1778 kJ of energy is released.
Important Notes:

The unit kJ / mol for  H represents the energy released or absorbed in kJ per molar
amounts, as specified in the balanced chemical equation.

The amount of energy produced or released during a chemical process is directly
proportional to the amount (in mole) of substance reacting. Therefore:
If the coefficients of a chemical reaction are trebled, the  H value must also treble in
value.
6C2 H 6( g )  21O2( g )  12CO2( g )  18H 2O( g )

As endothermic and exothermic reactions are opposite processes, when an equation is
reversed, the  H value changes in sign.
2Mg( s )  O2 ( g )  2MgO( s )
2MgO( s )  2Mg ( s )  O2 ( g )

H  (3  1778) kJ / mol
H   1204 kJ / mol
H   1204 kJ / mol
Thermochemical equations must include:
The physical state of each species, as changes in state require different energy
changes. For example:
H 2 O( s )  H 2 O(l )
H  6 kJ / mol
H 2 O(l )  H 2 O( g )
H  44 kJ / mol

A positive or negative sign in front of the  H value.

Unless otherwise specified:
 H values are reported for the forward reaction.
Enthalpies are reported at 25°C.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 3
QUESTION 1
The combustion of methane is described by the following equation:
CH 4( g )  2O2 ( g )  CO2 ( g )  2 H 2 O( g )
H  890 kJ / mol
(a)
How much energy would be released when 2.00 mole of methane is combusted?
(b)
What energy change would occur as the result of combusting 8.00 g of methane?
Solution
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 4
CALCULATIONS INVOLVING THERMOCHEMICAL EQUATIONS
Example:
Find the energy released when 4.500 mol of oxygen reacts completely with ethane.
2C2 H 6( g )  7O2 ( g )  4CO2 ( g )  6 H 2O( g )
H  1778 kJ / mol
You want to find
the energy
released for 4.5
mole of oxygen.
E released 1778

4.500
7
From the balanced
equation you know that
1778 kJ of energy is
released for 7 mol of
oxygen.
1778
 4.50
7
 1143 kJ
E released 
Note:
Always think carefully about the sign of your answer which will depend on the way the
question was phrased.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 5
QUESTION 2
The equation for the combustion of octane is:
2C8 H18( l )  25O2( g )  16CO2( g )  18H 2O( g )
H  10,900 kJmol 1
(a)
What mass of oxygen would be needed to release 8516 kJ of heat?
(b)
Calculate the mass of CO2 that would be produced, and the associated energy
change, when 630 g of octane is burnt
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 6
ENERGY FROM FUELS
The energy from fuels can be determined experimentally by combusting a known quantity of
fuel and measuring the energy released. If the energy released is used to heat water, then
the temperature change of the water will be proportional to the energy released by the fuel.
Converting the temperature change of the water to the energy released by the fuel is done
using the specific heat capacity of water.
THE SPECIFIC HEAT CAPACITY OF WATER
The specific heat capacity of water is the amount of energy needed to increase one gram of
water by one degree Celsius (or 1 Kelvin).
Water has a specific heat capacity of
Therefore,
of energy is required to raise the temperature of
.
g of water by
.
The specific heat capacity may have different units depending on the unit for energy, mass
and temperature. However, J g 1 C 1 is the most common unit used for SHC in VCE
Chemistry.
The energy gained or lost by a substance can be determined from its heat capacity, mass
and temperature change.
E  mc E = Energy lost or gained (J)
m = mass (g)
c = heat capacity of the substance being heated ( J g 1 C 1 )
 = change in temperature ( C )
Note:
m
).
V

The mass of the substance being heated can be determined from its density ( d 

The density of water is 1 g ml 1 .

Since solutions are mainly water, you may assume that their density is the same a
water unless otherwise stated.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 7
QUESTION 3
How much energy is required to raise the temperature of 100 ml of water by 10°C?
Solution
QUESTION 4
What change in temperature will result from 2.0 kg of water being supplied with 20.0 kJ of
energy?
Solution
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 8
EXPERIMENTAL DETERMINATION OF
ENTHALPY OF COMBUSTION

A known amount of fuel is burnt.

The energy released is used to heat a known
amount of water.

The temperature change and specific heat capacity
of the water is used to determine the energy that
was transferred from the fuel to the water.

The energy of the fuel is calculated in kJ mol 1 ,
kJ L1 or kJ g 1 .
Note:
When the heat content of a fuel is calculated in this way,
it will always be less than the true value since there is
not a 100% transfer of chemical energy from
the fuel into the water. Some heat will be lost to the
environment and some will be used to heat up the
container holding the water.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 9
QUESTION 5
A propane burner place under a beaker containing 0.500 L of water and was used to
combust 1.540 g of the gas. The temperature of the water increased by 30.00 K.
(a)
Calculate the molar heat of combustion of the fuel.
(b)
The theoretical value for the molar heat of combustion for propane is 2217 kJ mol 1 .
Explain why this value is different to the value calculated in part (a).
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 10
(c)
What experimental procedures should be put in place to minimise energy loses from
the combustion of the propane?
(d)
A second experiment was completed, this time using butane. In order to compare the
molar heat of combustion of the two fuels accurately, what experimental conditions
must be kept constant?
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 11
QUESTION 6
The equations for the combustion of octane is shown below.
2C8 H18(l )  25O2( g )  16CO2( g )  18H 2 O(l )
(a)
H  10,900 kJ / mol
If octane has a density of 0.703 g ml 1 , what would be the temperature change in
1.00 L of water when heated by the combustion of 5.00 ml of octane?
(Assume that 20.0% of the energy is not transferred into the water.)
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 12
(b)
Assuming the same efficiency as in part (a), calculate the amount of octane needed to
heat 1.000 L of water by 50°C.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 13
SOURCING FUELS
Non-renewable energy sources are fuels that are finite and will run out, as they are
consumed at a rate faster than they can be produced. Examples include fossil fuels (coal, oil
and gas) as well as nuclear materials.
Rate of Production ≤ Rate of Consumption
Renewable sources can be replaced by natural processes within a relatively short period of
time. Examples include: Wind, tides, waves, biofuels (from plant and animal matter), the sun.
Rate of Production ≥ Rate of Consumption
As our main current energy sources are derived from non-renewable fuels, there is an urgent
need for the development of alternative fuels to meet future energy requirements.
CARBON NEUTRAL FUELS
The energy in carbon based fuel is released via combustion. The reaction produces carbon
dioxide which inevitably ends up in the atmosphere.
Fuel + Oxygen  Carbon Dioxide + Water
Carbon neutrality means that producing and burning a carbon based fuel will not increase
the carbon (as CO2 ) in the atmosphere. This is only possible if the amount of carbon
released into the atmosphere when the fuel is burn is also extracted from the atmosphere in
roughly the same time frame.
From a scientific perspective, a fuel is deemed carbon neutral if:

The use of that fuel to produce energy does not result in the emission of carbon
compounds into the atmosphere. For example, nuclear energy.

The time it takes to produce the fuel and recycle the carbon released into the
atmosphere when that fuel is combusted is much shorter than the amount of time
before global warming effects occur i.e. a few years.

For example, biofuels produced from plants are carbon neutral as the CO2 absorbed
from the air as a plant grows cancels out the CO2 emitted when it is burned and as this
process (complete recycling of carbon) takes place within a few years.
Note:
When fuels are described as carbon neutral, this often doesn’t take into account the carbon
dioxide released in the production or transportation of the fuel.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 14
QUESTION 7
The world faces an energy crisis because:
A
B
C
D
The demand for energy continues to increase
World oil production cannot continue to increase
Potential fuel shortage threaten economic and political stability
All of the above
QUESTION 8
Which of the following fuels is both renewable and has relatively small carbon footprint?
A
B
C
D
Nuclear energy
Coal
Natural gas
Petroleum
QUESTION 9
Fossil fuels are non-renewable since:
A
B
C
D
Once used up, they can never be replaced.
The planet is unable to generate enough organic material to replace them.
They increase the amount of carbon dioxide in the atmosphere.
They are used up at a faster rate than they can be replaced.
QUESTION 10
Biofuels are considered carbon neutral since:
A
B
C
D
They release no carbon dioxide into the atmosphere.
They release no carbon into the atmosphere.
They can be replace at a rate greater or equal to their rate of consumption.
The amount of carbon dioxide absorbed to produce the biomass is equal to the amount
released when the fuel is burnt.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 15
FOSSIL FUELS AND BIOFUELS
Although there are many types of fuels used around the world, the highest proportion of
useable energy comes from fossil fuels and biofuels. These two fuel sources will be the
focus of Unit 3 Chemistry.
FOSSIL FUELS
Fossil fuels are non-renewable sources of energy and
are produced from the incomplete decay of animal and
plant material. The main types fossil fuels include:



Coal
Crude Oil/ Petroleum
Natural Gas (including Coal Seam Gas)
Fossil fuels are found in deposits within the Earth
(some which occur under the ocean floor) and are
comprised of carbon rich and energy dense
molecules.
Coal  mainly comprised of carbon.
Crude oil and natural gas  mainly a mixture of hydrocarbons.
Coal seam gas  mainly methane which is trapped in coal deposits.
ENVIRONMENTAL CONSIDERATIONS

Fossil fuels are NON – RENEWABLE since: The rate they are consumed > The rate
they are formed.

Fossil fuels are NOT CARBON NEUTRAL since the rate of CO2 production > rate
CO2 is removed from the atmosphere.

The burning of fossil fuels by humans is the largest source of emissions of carbon
dioxide, which is a greenhouse gases and a major contributor to global warming.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 16
BIOFUELS
As our main current energy sources are derived from non-renewable fuels, there is an urgent
need for the development of alternative fuels to meet future energy requirements.
Biochemical fuels (biofuels) are one of these alternatives, as they are renewable and are
less polluting than coal or oil.
Biochemical fuels are derived from organic materials, predominantly plants e.g. starch,
wheat, sugar cane and vegetable oils. These fuels are generally formed via endothermic
processes, so they have high levels of chemical potential energy which can be released as
heat upon burning.
There are three types of biochemical fuels (biofuels):

Biomass

Biogas

Liquid fuels
RENEWABILITY
To be renewable, an energy source has to be able to be replenished within the time frame
that it is consumed. Biofuels are considered renewable since the plants from which they are
derived can be replaced at the same rate that they are consumed to produce the biofuels.
CARBON NEUTRALITY
In simplistic terms, biofuels can be considered to be carbon neutral since the carbon dioxide
they produce is taken up by plants when new biofuel crops are grown. In this way there is no
net increase in the amount of carbon dioxide in the atmosphere.
Unfortunately, this does not take into account the energy consumed and carbon dioxide
emitted when biofuel crops are grown, processes and transported. When these factors are
taken into account, then biofuels are not carbon neutral.
Fossil Fuel Inputs:
Pesticides
Fertilisers
© The School For Excellence 2017
Biofuels
Fuel for transport
Fuel for machinery
Succeeding in the VCE – Unit 3 Chemistry
Page 17
BIOMASS
Biomass is a fuel produced directly or indirectly by biological resources. Biomass is the term
used for all organic material originating from plants or animals. The energy contained in
these fuels originates from the sun and has been trapped via photosynthesis.
Photosynthesis:
6CO2 ( g )  6 H 2O(l ) chlorophyl
  light
 C6 H12O6( aq )  6O2 ( g )
Converted to complex
carbohydrates
Biomass
Plants process the glucose that is produced in plants into complex carbohydrates. It is the
energy that is trapped within these compounds that is released upon combustion.
Combustion of biomass transforms the chemical energy stored within the chemical bonds of
the fuel to heat energy, which may then be used as an energy source.
A simplified representation of the combustion reaction for biomass is:
Biomass  O2 ( g )  CO2( g )  H 2O( g )  Heat
Biomass is the starting material for all biofuels. The original biomass crops
get processed into biofuels such as biomethane, bioethanol and biodiesel.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 18
QUESTION 11
Biomass can be converted into:
A
B
C
D
Solid fuel
Liquid fuel
Gaseous fuel
All of the above
QUESTION 12
Using biomass as an energy source is considered more environmentally friendly than
burning fossil fuels because:
A
B
C
D
Biomass produces no greenhouse gases.
Sourcing biomass has no environmental impacts.
There is enough naturally occurring biomass to meet demands.
The growth of biomass crops reduces the amount of carbon dioxide in the atmosphere.
QUESTION 13
What is one disadvantage of bioethanol?
A
B
C
D
Bioethanol can be viewed as a carbon neutral fuel
Arable land is needed for bioethanol production
Bioethanol is renewable
Bioethanol production provides a use for excess sugar crops
QUESTION 14
Which of the following are examples of how biomass can be converted into useful energy?
i. Burning animal dung to cook food.
ii. Converting left over cooking oil to biodiesel.
iii. Converting sugar cane into ethanol.
A
B
C
D
i and ii
i and iii
ii and iii
i, ii and iii
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 19
ENVIRONMENTAL IMPACTS OF COMBUSTING FUELS:
BIOFUELS AND FOSSIL FUELS
The burning of fuels has enormous environmental impact due to the variety of toxic
chemicals that can be released into the environment. Some of these chemicals include:





Carbon dioxide
Nitrous oxides
Sulfur dioxide
Heavy metals
Particulate matter
THE GREENHOUSE EFFECT
Complete Combustion
The complete combustion of fossil fuel is the most desirable reaction since it releases the
largest amount of energy per amount of fuel.
Fuel + Oxygen  Carbon Dioxide + Water + ENERGY
The carbon dioxide and water produced in this reaction are greenhouse gases.
This means they absorb infrared radiation which results in a gradual increase in the overall
temperature of the earth's atmosphere. Since the amount of water vapour in the atmosphere
is short lived (since it regularly falls as rain or snow), it is the additional carbon dioxide from
combustion that has the greatest effect on global warming.
The Greenhouse Effect involves:
1.
Solar radiation from the Sun hits our atmosphere.


Some is reflected back into space.
Some reaches the Earth’s surface and is absorbed by land and water.
2.
The heat from the surface of the Earth, radiated back towards space.
3.
Some of this heat is trapped which provides the warmth needed for life to exist.
4.
The enhanced Greenhouse effect occurs due to the increased amounts of greenhouse
gases in the atmosphere due to human activities. This traps extra heat, causing the
Earth’s temperature to rise.
The Earth’s average temperature has warmed by about 0.76°C over the past 100 years, with
most of this warming occurring in the past 20 years. This warming has been scientifically
proven to be a result of human activity such as burning fossil fuels. Although these
temperature increases are small, the implications for the environment are huge.
© The School For Excellence 2017
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Page 20
What does a 0.76°C temperature rise mean?

More hot days

More severe storms, floods, droughts and fire

Higher sea levels

More pressure on water supplies

Melting of the polar ice caps

Sea level rises

Reduced oxygen solubility in water

Increased acidity of the oceans
Other principle greenhouse gases include, methane and nitrogen oxides. While most of
these gases occur in the atmosphere naturally, levels have been increasing due to the
widespread burning of fuels by growing human populations.
It is predicted that average global temperatures are going to continue to increase by as
much as 4°C by 2100 if greenhouse gas emissions cannot be controlled. This will radically
change the world’s climate and place astronomical demands of food production and water
security.
Since 72% of emitted greenhouse gases is carbon dioxide, it is essential that
environmentally friendly alternatives are found for electricity production or that the carbon
dioxide produced is neutralised via schemes such as carbon sequestration or carbon
trading.
Carbon dioxide also contributes to acid rain since it can react with water to form a weak acid.
CO2 ( g )  H 2O(l )  H 2CO3( aq )
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 21
QUESTION 15
The burning of which fuel would reduce the build-up of carbon dioxide in the atmosphere?
A
B
C
D
Ethanol
Diesel
Methane
Hydrogen
QUESTION 16
The natural greenhouse effect is mainly caused by:
A
B
C
D
The trapping of solar energy as it enters the Earth’s atmosphere.
The trapping of energy as it irradiates from the Earth’s surface back into space.
The increase in carbon dioxide levels in the atmosphere due to human activity.
The deforestation of the planet.
QUESTION 17
Which of the following is not a greenhouse gas?
A
B
C
D
Water vapour
Oxygen
Nitrous oxide
Carbon dioxide
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 22
QUESTION 18
Which of the following greenhouse gases is most abundant in the atmosphere?
A
B
C
D
Methane
Carbon dioxide
Water
Nitrous oxide
QUESTION 19
The largest source of non-natural carbon dioxide emissions into the atmosphere comes
from:
A
B
C
D
Energy supply
Transport
Agriculture
Wood fires
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 23
CALCULATIONS INVOLVING GASES
When making fuel choices, there are a number of considerations to take into account.

How much energy is stored in the fuel per mass, volume or mole?

What is the energy efficiency of the fuel?

How much greenhouse gas will be produced per unit of fuel?

How much energy is produced per unit of greenhouse gas?

How much room will be needed to store the fuel?
Some of the answers to these questions can be obtained via stoichiometric calculations.
These calculations will require a combination of the following concepts.

Stoichiometric calculations using mole ratios from balanced equations via masses or
volumes.

Limiting reactant stoichiometry.

Molar volumes of gases.

Thermochemical Equations.

Molar Enthalpies or Molar Heat of Combustion.

The General Gas Equation.

Volume Ratios of Gases.

Density values.

The heat capacity of water.
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Succeeding in the VCE – Unit 3 Chemistry
Page 24
THE GENERAL GAS EQUATION
The general gas equation is developed from the combined gas equation by determining a
value for k (the constant from combined relationship). It is given the symbol R and so the
equation becomes:
PV=nRT
P  Pressure ( kPa )
V  Volume ( L )
n  Amount (in mol) of gas ( mol )
1
R  Gas constant = 8.31 JK mol
1
T  Temperature ( K )
Useful Conversions:
760 mmHg = 1 atmosphere = 101,325 Pa = 101.325 kPa
3
1 dm = 1000 ml = 1 L
3
1 cm = 1 ml
Temperature (K)= Temperature ( C ) + 273
Note:
The gas constant only has a value of 8.31 if the correct units are used as shown above.
© The School For Excellence 2017
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Page 25
QUESTION 20
At what temperature, in degrees Celsius, will 0.0750 mol of CO2 occupy 2.75 L at 1.11 atm?
Solution
QUESTION 21
What amount, in mole, of O2 is present in a 0.50 L sample at 25°C and 1.09 atm?
Solution
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Page 26
QUESTION 22
Ethanol ( CH 3CH 2OH ) is increasingly being used as an alternative to petrol, which mainly
consists of octane ( C8 H18 ). The density of ethanol is 0.789 g ml 1 .
C2 H 5OH (l )  3O2( g )  2CO2( g )  3H 2O(l )
H  1364 kJ / mol
A typical fuel tank holds 70.0 L of fuel.
(a)
What volume of ethanol would be present in a full tank of E10 petrol?
(b)
Calculate the volume of carbon dioxide produced from the ethanol in the tank given
conditions of 25°C and atmospheric pressure.
(c)
Does burning 7.00 L of ethanol increase the net amount of carbon dioxide to the
atmosphere by the amount calculated in part (b)? Explain.
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Succeeding in the VCE – Unit 3 Chemistry
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QUESTION 23
In a laboratory experiment, 10.00 g of methanol was combusted with 9.000 L of pure
oxygen. The temperature and pressure in the laboratory was 22°C and 104 kPa .
(Conditions were not held constant.)
(a)
Calculate the total mass of greenhouse gases produced.
(b)
What mass of greenhouse gas is produced per unit of energy?
State your answer in g kJ 1 .
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 28
SUCCEEDING IN THE VCE 2017
UNIT 3 CHEMISTRY
STUDENT SOLUTIONS
FOR ERRORS AND UPDATES, PLEASE VISIT
WWW.TSFX.COM.AU/VCE-UPDATES
QUESTION 1
(a)
1.78 × 103 kJ
(b)
445 kJ would be released.
QUESTION 2
(a)
625 g
(b)
3.01× 10 4 kJ of energy was released
QUESTION 3
4.2 kJ
QUESTION 4
2.4 °C
QUESTION 5
(a)
1791 kJ/mol
(b)
Not all of the energy from the propane is transferred to the water, some is lost as heat
and is not accounted for in the calculations making the molar heat of combustion lower
than it should be.
(c)
Insulate the beaker.
Place the beaker close to the flame.
Make sure there is a good supply of oxygen to ensure complete combustion.
Place a cover over the beaker.
(d)
Distance between beaker and flame.
Size and shape of the beaker.
Amount of insulation.
Same cover for beaker.
Same volume of water.
Same amount of gas.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 1
QUESTION 6
(a)
32.2 °C
(b)
5.46 g
QUESTION 7
Answer is D
QUESTION 8
Answer is A
QUESTION 9
Answer is D
QUESTION 10
Answer is D
QUESTION 11
Answer is D
QUESTION 12
Answer is D
QUESTION 13
Answer is B
QUESTION 14
Answer is D
QUESTION 15
Answer is D
QUESTION 16
Answer is B
QUESTION 17
Answer is B
QUESTION 18
Answer is C
QUESTION 19
Answer is A
QUESTION 20
223 °C
QUESTION 21
0.0223 mol
QUESTION 22
(a)
7.00 L
(b)
5.87 ×10 3 L
(c)
Yes if the ethanol was sourced from fossil fuels since no carbon dioxide is removed
from the atmosphere by its production or combustion.
No if the ethanol was sourced from biomass. In this case, some of the carbon dioxide
released would be offset by the carbon dioxide absorbed when the crop was growing.
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 2
QUESTION 23
(a)
m( greenhouse gases) = 20.4 g
(b)
Greenhouse gases emitted = 0.110 g kJ −1
© The School For Excellence 2017
Succeeding in the VCE – Unit 3 Chemistry
Page 3