Explain how decreasing temperature in an exothermic reaction influences the rate of a chemical reaction. (2 marks)
--- 5 WORK AREA LINES (style=lined) ---
Aussie Maths & Science Teachers: Save your time with SmarterEd
Explain how decreasing temperature in an exothermic reaction influences the rate of a chemical reaction. (2 marks)
--- 5 WORK AREA LINES (style=lined) ---
→ In an exothermic reaction, heat is released as the reaction progresses from the reactants to the products.
→ Decreasing the temperature in an exothermic reaction leads to a decrease in the reaction rate.
→ A decrease in temperature lowers the kinetic energy of particles which leads to less successful collisions that exceed activation energy
→ In an exothermic reaction, heat is released as the reaction progresses from the reactants to the products.
→ Decreasing the temperature in an exothermic reaction leads to a decrease in the reaction rate.
→ A decrease in temperature lowers the kinetic energy of particles which leads to less successful collisions that exceed activation energy
--- 2 WORK AREA LINES (style=lined) ---
--- 8 WORK AREA LINES (style=lined) ---
i. Differentiation:
→ The difference in shape and size between different cells in a multicellular organism due to their specialised function.
ii. Multicellular organisms require specialised cells:
→ Multicellular organisms are large organisms which require many complex internal processes to function.
→ To be more effective, multicellular organisms have specialised cells. Specialised cells have a certain shape, size and number and type of organelles.
→ Cell specialisation allows cells to perform one specific role to benefit the whole organism rather than every individual cell performing every function.
→ This makes multicellular organisms able to carry out many complex functions while still remaining energy efficient.
i. Differentiation:
→ The difference in shape and size between different cells in a multicellular organism due to their specialised function.
ii. Multicellular organisms require specialised cells:
→ Multicellular organisms are large organisms which require many complex internal processes to function.
→ To be more effective, multicellular organisms have specialised cells. Specialised cells have a certain shape, size and number and type of organelles.
→ Cell specialisation allows cells to perform one specific role to benefit the whole organism rather than every individual cell performing every function.
→ This makes multicellular organisms able to carry out many complex functions while still remaining energy efficient.
Explain how increasing temperature in an endothermic reaction influences the rate of a chemical reaction. (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
→ In an endothermic reaction heat is absorbed as the reaction progresses from reactants to products.
→ An increase in temperature raises the kinetic energy of particles and leads to more successful particle collisions that exceed activation energy
What are the valencies of the following simple ions
--- 1 WORK AREA LINES (style=lined) ---
--- 1 WORK AREA LINES (style=lined) ---
--- 1 WORK AREA LINES (style=lined) ---
i. Valency: Barium
ii. Valency: Phosphide
iii. Valency: Silver
i. Valency: Barium
ii. Valency: Phosphide
iii. Valency: Silver
Draw Lewis electron dot structures for the following ionic molecular compounds
--- 4 WORK AREA LINES (style=lined) ---
--- 4 WORK AREA LINES (style=lined) ---
--- 4 WORK AREA LINES (style=lined) ---
Draw Lewis electron dot structures for
--- 3 WORK AREA LINES (style=lined) ---
--- 3 WORK AREA LINES (style=lined) ---
i.
ii.
i.
ii.
When proteins are broken down in chemical digestion, they become
→ Proteins are broken down so as their beneficial components can be absorbed in the small intestine.
→ Amino acid chains (called polypeptide chains) make up all proteins, and are hence the smallest unit of a protein possible in chemical digestion.
A soccer ball leaves the ground with a velocity of 10 ms
--- 4 WORK AREA LINES (style=lined) ---
--- 4 WORK AREA LINES (style=lined) ---
i.
ii.
i.
ii.
A ball is thrown vertically upwards from ground level, it gains 50 metres vertically and then falls back to the ground.
--- 4 WORK AREA LINES (style=lined) ---
--- 4 WORK AREA LINES (style=lined) ---
i.
ii.
i.
ii.
Complete the table below by outlining one physical indication of each chemical change described below. (3 marks)
--- 0 WORK AREA LINES (style=lined) ---
Outline both a physical and chemical property of the elements contained in the highlighted periodic table groups below. (4 marks)
--- 6 WORK AREA LINES (style=lined) ---
Group
→ Physical properties: Group 1 metals are soft and shiny.
→ Chemical properties: They are highly reactive and have low melting/boiling points.
Group
→ Physical properties: Group 8 elements are colourless gases with no odour or taste.
→ Chemical properties: They are virtually unreactive and all have cryogenic boiling points.
Group
→ Physical properties: Group 1 metals are soft and shiny.
→ Chemical properties: They are highly reactive and have low melting/boiling points.
Group
→ Physical properties: Group 8 elements are colourless gases with no odour or taste.
→ Chemical properties: They are virtually unreactive and all have cryogenic boiling points.
Name the following inorganic compounds:
--- 1 WORK AREA LINES (style=lined) ---
--- 1 WORK AREA LINES (style=lined) ---
i. Sulfuric Acid
ii. Sulfurous Acid
Name the following inorganic compounds:
--- 1 WORK AREA LINES (style=lined) ---
--- 1 WORK AREA LINES (style=lined) ---
i. Magnesium Carbonate
ii. Mercury Bromide
Calculate the mass of
--- 4 WORK AREA LINES (style=lined) ---
Greenhouses have been used to generate higher crop yields than open-field agriculture. To encourage plant growth in greenhouses, the conditions required for photosynthesis are controlled. Commercial greenhouses, like the ones shown below, often use a lot of energy for heating, ventilation, lighting and water.
--- 5 WORK AREA LINES (style=lined) ---
--- 4 WORK AREA LINES (style=lined) ---
a. Temperature maintenance:
→ Photosynthesis is regulated by different enzymes which are intrinsic to numerous processes involved in photosynthesis.
→ If the temperature of a greenhouse is changed, then the enzymes may decrease in activity or denature, causing a reduction in the rate of photosynthesis or even ceasing it all together.
→ This can cause problems in the plants such as a reduction in growth or plant death.
b. Crop yield increases:
→ Red wavelengths of light are used during photosynthesis, while green light is reflected off the plants.
→ This technology will allow an increase in crop yields by increasing the amount of red light which increases the rate of photosynthesis.
a. Temperature maintenance:
→ Photosynthesis is regulated by different enzymes which are intrinsic to numerous processes involved in photosynthesis.
→ If the temperature of a greenhouse is changed, then the enzymes may decrease in activity or denature, causing a reduction in the rate of photosynthesis or even ceasing it all together.
→ This can cause problems in the plants such as a reduction in growth or plant death.
b. Crop yield increases:
→ Red wavelengths of light are used during photosynthesis, while green light is reflected off the plants.
→ This technology will allow an increase in crop yields by increasing the amount of red light which increases the rate of photosynthesis.
A light ray from a laser passes from a glucose solution
--- 2 WORK AREA LINES (style=lined) ---
--- 0 WORK AREA LINES (style=lined) ---
--- 6 WORK AREA LINES (style=lined) ---
a.
→ When the light strikes the surface at an angle greater than the critical angle, Total Internal Reflection will occur.
→ As a result of the total internal reflection, all the light will be reflected off the boundary back into the glucose solution and therefore will not travel to the observer.
a. | ||
c. Observer cannot see the laser:
→ When the light strikes the surface at an angle greater than the critical angle, Total Internal Reflection will occur.
→ As a result of the total internal reflection, all the light will be reflected off the boundary back into the glucose solution and therefore will not travel to the observer.
Ancient cave drawings contribute evidence of cognitive changes that are unique to modern humans, Homo sapiens. Biologists argue that these unique cognitive changes in H. sapiens allowed cultural evolution that would have been impossible in other hominin species.
--- 4 WORK AREA LINES (style=lined) ---
A team of scientists dated the mineral deposits in the solid, transparent layer using uranium-thorium dating. They found that some of the mineral deposits are 65 000 years old.
What conclusion can be made about the age of the ancient drawings on the stalagmites? Justify your response. (2 marks)
--- 3 WORK AREA LINES (style=lined) ---
|
|
|
--- 5 WORK AREA LINES (style=lined) ---
a. Answers could include two of the following:
→ Cave drawings show information being passed through generations.
→ The paintings often depict changing hunting techniques or dreaming stories over time.
→ Increasing complexity of these cave drawings over time shows the development of complex thought and symbolic relationships in H. sapien tribes.
b. → The drawings must be a minimum of 65,000 years old.
→ This is because they must be at least as old as the mineral layer on top of them.
c. → H. sapiens are believed to have arrived in Europe 45,000 years ago.
→ The dating shows the drawings are a minimum of 65,000 years old.
→ Therefore the data suggests that either H. neanderthalensis drew the art, or H. sapiens arrived earlier than currently believed.
a. Answers could include two of the following:
→ Cave drawings show information being passed through generations.
→ The paintings often depict changing hunting techniques or dreaming stories over time.
→ Increasing complexity of these cave drawings over time shows the development of complex thought and symbolic relationships in H. sapien tribes.
b. → The drawings must be a minimum of 65,000 years old.
→ This is because they must be at least as old as the mineral layer on top of them.
c. → H. sapiens are believed to have arrived in Europe 45,000 years ago.
→ The dating shows the drawings are a minimum of 65,000 years old.
→ Therefore the data suggests that either H. neanderthalensis drew the art, or H. sapiens arrived earlier than currently believed.
Lee listens while a police car with a loud siren comes towards her, travels past her and then continues on away from her.
Compared with the sound she would hear from the siren if the police car were stationary, the sound has.
→ By the application of the doppler effect, the frequencies of sounds increase when moving towards an object and decrease when moving away from an object.
A model car of mass 2.0 kg is propelled from rest by a rocket motor that applies a constant horizontal force of 4.0 N, as shown below. Assume that friction is negligible.
With the same rocket motor, the car accelerates from rest for 10 seconds.
Calculate the the final speed of the model car? (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
A model car of mass 2.0 kg is propelled from rest by a rocket motor that applies a constant horizontal force of 4.0 N, as shown below. Assume that friction is negligible.
Which one of the following best gives the magnitude of the impulse given to the car by the rocket motor in the first 5.0 seconds?
Two large charged plates with equal and opposite charges are placed close together, as shown in the diagram below.
A distance of 5.0 mm separates the plates. The electric field between the plates is equal to 1000 N C
Calculate the voltage difference between the plates. (2 marks)
Voltage difference is
Figure 13 shows two speakers,
Take the speed of sound to be 340 ms
--- 2 WORK AREA LINES (style=lined) ---
--- 7 WORK AREA LINES (style=lined) ---
a.
b. → At the centre of the speakers, there is an area of relative loudness
→ This is due to a path difference of 0 metres between the wavelengths of sounds coming from both speaker
→ As the student moves towards speaker
→ The peak of speaker
→ The second region of quietness (node) will be half of a wavelength (0.5m) from the first region of quietness. Thus, the total distance from the centre to the second region of quietness is 0.75m.
a.
b. → At the centre of the speakers, there is an area of relative loudness
→ This is due to a path difference of 0 metres between the wavelengths of sounds coming from both speaker
→ As the student moves towards speaker
→ The peak of speaker
→ The second region of quietness (node) will be half of a wavelength (0.5m) from the first region of quietness. Thus, the total distance from the centre to the second region of quietness is 0.75m.
Alex hears the siren from a stationary fire engine.
Compared with the sound Alex hears from the stationary fire engine, the sound Alex will hear as the fire engine approaches him will have increased
→
→
A railway truck
The final speed of the joined railway trucks after the collision is closest to
The collision of the railway trucks is best described as one where
→ By the law of conservation of momentum:
→ By the law of conservation of momentum, momentum in the collision is conserved.
→ Kinetic energy conservation:
|
||
→ The kinetic energy of the system decreases after the collision and so is not conserved.
A straight wire carries a current of 10 A.
Which one of the following diagrams best shows the magnetic field associated with this current?
→ Using the right hand grip rule, the thumb points up and the fingers curl in an anticlockwise direction as seen from above.
In an experimental set-up used to investigate standing waves, a 6.0 m length of string is fixed at both ends, as shown in Figure 12. The string is under constant tension, ensuring that the speed of the wave pulses created is a constant 40 ms
In an initial experiment, a continuous transverse wave of frequency 7.5 Hz is generated along the string.
--- 3 WORK AREA LINES (style=lined) ---
--- 4 WORK AREA LINES (style=lined) ---
a.
b. → A standing wave will not form.
→ A standing wave will form only if the wavelength of the wave is equal to an integer multiple
a.
b. → A standing wave will not form.
→ A standing wave will only form if the length of the string is equal to an integer multiple of
→ Since 6.0 m is not an integer multiple of
The graph below shows when the five major mass extinction events and several other mass extinction events occurred. It also shows the percentage of species that were lost in each event.
According to the graph, to be classified as a major mass extinction event, the percentage of species that are lost has to be at least
→ The lowest % of species lost in a mass extinction event is 74% within this data set.
→ It follows that for an extinction event to be classified as major, at least 74% of species must have been lost.
In a series of experiments, the rate of photosynthesis in plant cells was measured in environments with different concentrations of carbon dioxide. All other variables were kept constant.
Which one of the following graphs reflects the trend that would be shown by the results of these experiments?
→ As carbon dioxide is a reactant in photosynthesis, increasing the concentration will lead to a higher rate of photosynthesis initially.
→ This rate of increase will plateau and eventually stop as all the active sites of involved enzymes are being used.
→ If this relationship was graphed, the shape seen would most accurately resemble that in graph
A 3.1g sample of
--- 1 WORK AREA LINES (style=lined) ---
--- 4 WORK AREA LINES (style=lined) ---
--- 4 WORK AREA LINES (style=lined) ---
i.
ii. | ||
iii.
In the following reactions, predict whether entropy will increase or decrease, giving reasons. (3 marks)
i. → Decrease
→ 4 moles of gas becomes 2 moles of gas on the product side, causing the reaction to become more ordered and decreasing in entropy.
ii. → Increase
→ A solid decomposes into 2 moles of gas. This reaction becomes more disordered, and the phase change involves an increase in entropy.
iii. → Increase
→ An aqueous and solid reactant becomes an aqueous and gaseous product. The phase changes overall involve an increase in entropy.
i. → Decrease
→ 4 moles of gas becomes 2 moles of gas on the product side, causing the reaction to become more ordered and decreasing in entropy.
ii. → Increase
→ A solid decomposes into 2 moles of gas. This reaction becomes more disordered, and the phase change involves an increase in entropy.
iii. → Increase
→ An aqueous and solid reactant becomes an aqueous and gaseous product. The phase changes overall involve an increase in entropy.
Find the oxidation state of each element in the compound
--- 4 WORK AREA LINES (style=lined) ---
The oxidation state of phosphorus in the pyrophosphate ion
Which one of the following will not increase the rate of the above reaction?
In the above reaction, the number of successful collisions per second is a small fraction of the total number of collisions.
The major reason for this is that
→ Options
→ Successful collisions occur only if the particles involved have at least the minimum kinetic energy required and the correct orientation.
A helium balloon is inflated to a volume of 5.65 L and a pressure of 10.2 atm at a temperature of 25°C.
Calculate the amount of helium, in moles, in the balloon. (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
A home owner on a large property creates a backyard entertainment area. The entertainment area has a low-voltage lighting system. To operate correctly, the lighting system requires a voltage of 12
Calculate the power drawn by the lighting system. (3 mark)
--- 4 WORK AREA LINES (style=lined) ---
→ Using
→ The power drawn from the lighting system is 12
Figure 2 shows two equal positive stationary point charges placed near each other.
Sketch on Figure 2 the shape and direction of the electric field lines. Use at least eight field lines. (2 marks)
--- 0 WORK AREA LINES (style=lined) ---
→ Field lines must not touch.
→ Fields will repel one another.
An aerosol can with a volume of 300.0 mL contains 2.80 g of propane gas as a propellant. The warning label says the aerosol may explode at temperatures above 60.0 °C.
What is the pressure in the can at a temperature of 60.0 °C? (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
When concentrated sulfuric acid is added to dry sucrose,
An equation for the reaction is
Calculate the mass of carbon residue that could be produced by the reaction of 50.0 g of sucrose with excess concentrated sulfuric acid. (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
The electric field between two parallel plates that are 1.0 × 10
Calculate the voltage between the plates? (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
A 0.8 m long guitar string is set vibrating at a frequency of 250 Hz. The standing wave envelope created in the guitar string is shown in Figure 12.
--- 4 WORK AREA LINES (style=lined) ---
--- 0 WORK AREA LINES (style=lined) ---
a.
b.
a. |
||
b.
Two blocks of mass 5 kg and 10 kg are placed in contact on a frictionless horizontal surface, as shown in the diagram below. A constant horizontal force,
Which one of the following statements is correct?
If the force
Using Newton’s second Law:
→ The blocks will experience the same acceleration.
→ Both blocks will have the same force to mass ratio. Since the 5 kg block is half the mass of the 10 kg block, it will experience half the magnitude of the net force as the 10 kg block.
A distant fire truck travelling at 20 ms
Chris is standing on the edge of the road. Assume that the fire truck is travelling directly towards him as it approaches and directly away from him as it goes past. The arrangement is shown in Figure 14.
a.
a.
A small sodium lamp, emitting light of wavelength 589 nm, is viewed at night through two windows from across a street. The glass of one window has a fine steel mesh covering it and the other window is open, as shown in Figure 18. Assume that the sodium lamp is a point source at a distance.
A Physics student is surprised to see a pattern formed by the light passing through the steel mesh but no pattern for the light passing through the open window. She takes a photograph of the observed pattern to show her teacher, who assures her that it is a diffraction pattern.
--- 2 WORK AREA LINES (style=lined) ---
--- 6 WORK AREA LINES (style=lined) ---
a. Condition to satisfy:
→ The size of the gaps from the fine steel mesh must be of the same order of magnitude of the wavelengths of the light from the sodium lamp.
b. Open window differences:
→ The width of the window is significantly greater than wavelength of the light from the sodium lamp and the width of the glass molecules that make up the glass window is significantly smaller than the light from the sodium lamp.
→ These widths contrast greatly to the size of the steel mesh and are not of the same order of magnitude of the light from the sodium lamp, hence no diffraction will occur.
a. Condition to satisfy:
→ The size of the gaps from the fine steel mesh must be of the same order of magnitude of the wavelengths of the light from the sodium lamp.
b. Open window differences:
→ The width of the window is significantly greater than wavelength of the light from the sodium lamp and the width of the glass molecules that make up the glass window is significantly smaller than the light from the sodium lamp.
→ These widths contrast greatly to the size of the steel mesh and are not of the same order of magnitude of the light from the sodium lamp, hence no diffraction will occur.
Kym and Kelly are experimenting with trolleys on a ramp inclined at 25°, as shown in Figure 7. They release a trolley with a mass of 2.0 kg from the top of the ramp. The trolley moves down the ramp, through two light gates and onto a horizontal, frictionless surface. Kym and Kelly calculate the acceleration of the trolley to be 3.2 m s
--- 5 WORK AREA LINES (style=lined) ---
--- 5 WORK AREA LINES (style=lined) ---
--- 6 WORK AREA LINES (style=lined) ---
--- 6 WORK AREA LINES (style=lined) ---
a.i. See Worked Solutions
a.ii.
b.i.
b.ii. For the collision to be elastic, the kinetic energy must be conserved.
→ As the kinetic energy of the system decreases after the collision, it is not an elastic collision.
a.i. The gravitational force down the slope:
a.ii. | ||
b.i. By the conservation of momentum:
b.ii. For the collision to be elastic, the kinetic energy must be conserved.
→ As the kinetic energy of the system decreases after the collision, it is not an elastic collision.
Which one of the following statements best describes transverse and longitudinal waves?
→ The energy transfer through transverse waves is perpendicular to the direction of vibrations.
→ The energy transfer through longitudinal waves is parallel to the direction of vibrations.
Which one of the following statements best describes an observation of the Doppler effect for sound?
→ As a result of the Doppler effect, when there is relative movement towards a source of sound waves the frequency of the observed sound waves is increased.
A railway truck
After the collision, they are joined together and move off at speed
Which one of the following is closest to the mass of railway truck
Which one of the following best describes the force exerted by the railway truck
→ By the law of conservation of momentum, the momentum before the collision is equal to the momentum after the collision.
→ By Newton’s 3rd law of motion, each action has an equal and opposite reaction.
→ Hence, the force of
Victoria’s fossil emblem Koolasuchus cleelandi, shown on the stamp above, was chosen in January 2022.
K. cleelandi fossils have been found in Boonwurrung country in Gippsland. Studies of K. cleelandi fossils have revealed many interesting findings. Several of these findings are summarised below.
K. cleelandi findings
Part 1
Which combination of findings from the list above is most likely to be associated with an increased chance of formation of K. cleelandi fossils?
Part 2
It is most likely that scientists determined the absolute age of K. cleelandi fossils
→ K. cleelandi has large, dense bones (finding 2) which are less likely to decay overtime and hence have a higher chnace of being fossilised for a long period of time.
→ Because these bones are remaining in a river carrying many sediments (finding 4) the bones are more likely to be fossilised as they are covered quicker, reducing disturbance and hiding them from scavnegers.
→ Radioisotope dating of rocks is extremely accurate and reliable source of dating. Therefore it ios likely that scientists dated K. cleelandi fossils by dating the surrounding rock.
Enzymes are associated with the biochemical pathways of cellular respiration and photosynthesis.
Consider a cell that carries out both cellular respiration and photosynthesis.
Which one of the following is a correct statement about the enzymes associated with these pathways?
By Elimination
→ While the net chemical equations for photosynthesis and cellular respiration appear to be the reverse of each other, each reaction is made up of various processes which require different reaction conditions, including different enzymes (Eliminate A).
→ Enzyme concentrations can increase/decrease the amount of available active sites which can change the rate of reaction rate (Eliminate C).
→ A large increase in temperature would not increase reaction rate but would denature the enzymes (Eliminate D).
→ Changes in various factors, including pH, can denature an enzyme if the change is outside the optimal range for that factor.
The decomposition of ammonia is represented by the following equation.
--- 5 WORK AREA LINES (style=lined) ---
a.
b. → Tungsten will cause ammonia to decompose faster.
→ Faster rate due to lower activation energy.
→ Lower activation energy results in a greater proportion of successful collisions.
a.
b. → Tungsten will cause ammonia to decompose faster.
→ Faster rate due to lower activation energy.
→ Lower activation energy results in a greater proportion of successful collisions.
The energy profile diagram below represents a particular reaction. One graph represents the uncatalysed reaction and
the other graph represents the catalysed reaction.
Which of the following best matches the energy profile diagram?
A. | ||
B. | ||
C. | ||
D. |
→ The
→ The
The following energy profile shows the results obtained during an enzyme-catalysed reaction. Each stage of the reaction is labelled: M represents the initial reactants, N represents a stable intermediate and P represents the final products.
Which one of the following statements is correct?
--- 2 WORK AREA LINES (style=lined) ---
--- 6 WORK AREA LINES (style=lined) ---
a. Answers could include one of the following:
→ Heat loss into the surroundings from combustion process.
→ Specific examples of heat loss such as inefficient heating of water caused by proximity of the heat or not using a beaker lid.
b.
a. Answers could include one of the following:
→ Heat loss into the surroundings from combustion process.
→ Specific examples of heat loss such as inefficient heating of water caused by proximity of the heat or not using a beaker lid.
b.
Which statement explains why catalysts are often used in chemical reactions?
→ Catalysts increase the rate of reactions.
Hydrogen peroxide,
--- 6 WORK AREA LINES (style=lined) ---
--- 1 WORK AREA LINES (style=lined) ---
a. → Increasing the temperature will increase the rate of
→ An increase in temperature increases the kinetic energy of all molecules which causes both the frequency of collisions and the energy of each collision to increase.
→ The temperature increase results in more collisions, of which a higher proportion are successful (i.e. occur with greater energy than the activation energy threshold required to react).
b.
a. → Increasing the temperature will increase the rate of
→ An increase in temperature increases the kinetic energy of all molecules which causes both the frequency of collisions and the energy of each collision to increase.
→ The temperature increase results in more collisions, of which a higher proportion are successful (i.e. occur with greater energy than the activation energy threshold required to react).
b.
The correct equation for the incomplete combustion of ethanol is
→ The products of incomplete combustion are
Methane gas,
Write the balanced equation for the complete combustion of
--- 2 WORK AREA LINES (style=lined) ---
Bioethanol,
The mass of