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ice_blockie

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VCE Chemistry Revision Questions
« on: June 09, 2008, 05:09:12 pm »
+2
Hi there! Here is a list of some questions I wrote as revision. Mao and polky have posted solutions below (Unit 3 and Unit 4).

Unit 3 Revision Questions

AREA OF STUDY 1: CHEMICAL ANALYSIS

click here
1.  Give an example of some safety procedures that should be followed during experiment X involving volumetric analysis / gravimetric analysis?

2.  Suppose the actual percentage by mass of X obtained through gravimetric analysis was lower/higher than the calculated percentage. Suggest one reason how this may have come about.

3.  Suppose the actual concentration of X obtained through volumetric analysis was lower/higher than the calculated concentration. Suggest one reason how this may have come about.

4.  Explain the meaning of the term ‘primary standard’ and suggest why sodium hydroxide is not suitable for use as one.

5.  Explain how sodium hydroxide can be used to titrate sample X.

6.  Explain why the light is pulsed in atomic absorption spectroscopy.

7.  Which wavelength of light should be chosen to analyse sample X?

8.  Give possible reasons why compound X has a higher/lower Rf value than compound Y.

9.  Suggest why compound X has a higher/lower Rt value than compound Y.

10. What is the purpose of tetramethylsilane in NMR spectroscopy?

11. How is a suitable indicator chosen for a titration?

12. A student wanted to identify the concentration of compound X. A sample of compound X was taken and diluted in a volumetric flask. An aliquot of this diluted solution was then transferred to a conical flask. A burette was filled with compound Y. Which indicator should be added to the solution in the conical flask if X and Y were:
a) a weak acid and a weak base
b) a weak acid and a strong base
c) a strong acid and a strong base
d) a strong acid and a weak base

13. Briefly explain the principles of nuclear magnetic resonance spectroscopy.

14. Briefly explain the principles of infrared spectroscopy.

15. Briefly explain the principles of mass spectrometry.

16. What further experiment should be performed so that the exact concentration of compound X can be found? Consider GC, HPLC, AAS and UV Visible

AREA OF STUDY 2: ORGANIC CHEMICAL PATHWAYS

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1.  A mixture of different hydrocarbons was found to contain compound X, Y and Z. Given that X has the lowest boiling point and Z has the highest boiling point, explain how you could collect a pure amount of substance X, Y or Z.

2.  Explain how a bromine test can be used to determine saturation of a compound.

3.  Explain how proteins can act as markers for diseases, using an example of a specific disease to illustrate your answer.

4.  Explain what is meant by the term ‘biochemical fuels.’

5.  Explain why biochemical fuels are considered carbon neutral.

6.  Explain through the use of fully balanced equations how biodiesel can be produced from oleic acid.

7.  Explain the difference in chemical properties between starch and glycogen.

8.  What characteristic structure must an acid have to be classified as a 2-amino acid (α-amino acid)?

9.  Why is the action of an enzyme often described as operating like a ‘lock and key’?

9.  Describe how the activity of an enzyme is affected by a temperature increase.

10. Explain the significance of the tertiary structure of an enzyme to its biological activity.

11. Explain the effects of a change of pH on the biological activity of enzymes.

12. What is meant by the term ‘coagulation’?

13. Explain how an enzyme catalyses the reaction between compound X and Y.

14. What is the difference between the ‘primary’, ‘secondary’ and ‘tertiary’ structure of DNA?

15. Explain, using specific reference to the change in bonding, how DNA can replicate itself.

16. How does DNA control biochemical processes?

17. ‘A tiny change in DNA can lead to a variation in the sequence of amino acids in a protein, resulting in major health problems.’ Referring to a specific example, explain why this is the case.

18. What is meant by the term ‘polymerase chain reaction’?

19. Explain how the DNA fragments separate in gel electrophoresis.

20. Describe the process in which a DNA profile is constructed.

21. Explain why salicylic acid in its original form is not used as an analgesic.

22. Define the terms ‘atom economy’ and ‘percentage yield.’

Unit 4 Revision Questions

AREA OF STUDY 1: INDUSTRIAL CHEMISTRY

Reaction Rates

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1.   What are the conditions that need to be met so that a reaction occurs?

2.   What is the collision theory?

3.   What is activation energy?

4.   Explain in terms of collision theory how each of the following affects the rate of reaction:
a)   Concentration b) Pressure c) Temperature d) Surface Area e) Catalyst

5.   How does the reaction rate change with respect to time if the reaction is a) exothermic b) endothermic?

6.   Name two ways how the rate of a reaction could be monitored.
Equilibrium Reactions

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7.   What are equilibrium reactions?

8.   When is equilibrium reached?

9.   Why is equilibrium said to be dynamic?

10.   Given the equation A + B ↔ C + D, write the equilibrium constant for the reverse reaction.

11.   Explain the effect of a catalyst on the yield of a reaction.

12.   What is the difference between the concentration fraction and the equilibrium constant?

13.    When the concentration is smaller than the equilibrium constant, what will be the net reaction?

14.   When the concentration is larger than the equilibrium constant, what will be the net reaction?

15.   What does the magnitude of K tell us about an equilibrium reaction?

16.   How does K change with respect to time when the reaction is a) exothermic b) endothermic?

17.   State Le Chatelier’s principle.

18.   Using Le Chatelier’s principle, explain how each of the following affects the position of equilibrium:
a) addition of reactants or products b) changing the temperature
c) changing the pressure or volume d) dilution of system e) addition of catalysts 
f) addition of inert gases g) addition of water if water is also a reactant

19.   Explain why pure water has a pH of 7.

20.   When the temperature is increased, what is the effect on the pH of pure water?

21.   Give a typical equilibrium of a weak acid.

22.   Define a strong acid in terms of equilibrium.

23.   List the following acids from weakest to strongest: hydrofluoric acid, ethanoic acid, boric acid, nitrous acid, and lactic acid.

24.   Define percent ionisation.

25.   What is a buffer?
Waste Management

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26.   Define atom economy.

27.   Define ‘waste management’ and list some ways how waste can be ‘managed.’
Industrial production of a chemical

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28.   Give the formula and name of the chemical you have studied this year.

29.   Give the equilibrium reaction in the industrial production of your chemical and state whether it is exothermic or endothermic.

30.   List the conditions of temperature and pressure that would theoretically maximise yield and rate of the industrial production of your chemical.

31.   List the conditions of temperature and pressure that are actually used in the industrial production of your chemical explaining the difference, if any, between your answer to Q 30 and Q31.

32.   Write an equation where your chemical is a reactant.

33.   Write an equation where your chemical is a product.

34.   List 3 uses of your industrial chemical.

35.   Explain how the principles of green chemistry apply to the industrial production of your chemical.

36.   List two health and safety procedures that are followed in the industrial production of your chemical.

37.   Explain how waste management is applied to the industrial production of your chemical.

AREA OF STUDY 2: SUPPLYING AND USING ENERGY

Energy Sources

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1.   Explain the difference between the terms ‘renewable’ energy sources and ‘sustainable’ energy sources’.

2.   List 5 renewable and 3 non-renewable energy sources.

3.   Which energy sources currently do not commercially operate in Australia? Give reasons for your answer.
Thermochemistry

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4.   What is an energy profile?

5.   What is an endothermic reaction? What is an exothermic reaction?

6.   Draw a typical energy profile for an exothermic and an endothermic reaction.

7.   Define enthalpy in terms of bonding and energy.

8.   Name three important parts of a thermochemical equation.

9.   Explain the difference between heat capacity and heat of combustion.

10.   Explain why the heats of combustion of foods are given in kJ per gram rather than kJ per mol.

11.   Explain the function of a calorimeter.

12.   Give the names of two different types of calorimeters and describe their respective uses.

13.   Why do calorimeters need to be calibrated?

14.   Name three ways how a calorimeter can be calibrated.

15.   Name two ways how the actual value of the calibration factor could be higher than the calculated value.

16.   Name two ways how the actual value of the calibration factor could be lower than the calculated value.

17.   Name three formulas used in thermochemistry.
Electrochemistry

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18.   What is a redox reaction?

19.   Define oxidation, reduction, oxidant and reductant.

20.   State the rules for oxidation numbers.

21.   How do you write a balanced half equation?

22.   What is a galvanic cell?

23.   Explain the function of a salt bridge.

24.   Why are the half cells separated in a galvanic cell?

25.   Assign polarities to the cathode and the anode.

26.   Explain the properties that an electrode must have.

27.   Explain the choice of electrode if
a)   one member of the conjugate pair in a half cell is a metal
b)   no metal is present
c)   one member of the conjugate pair is a gas

28.   Explain how the electrochemical series can be used to predict redox reactions.

29.   Define potential difference.

30.   List three reasons why a predicted redox reaction does not occur.

31.   Explain the difference between a primary and a secondary cell.

32.   Explain why fuel cells are considered more efficient than power stations.

33.   Why are secondary cells able to be recharged but not primary cells?

34.   How do you recharge a secondary cell?

35.   What is the difference between a fuel cell and primary/secondary cells?

36.   What is electrolysis?
 
37.   Compare the similarities and differences between an electrolytic cell and a galvanic cell.

38.   Explain why the products of an electrolytic cell must not come into contact.

39.   In some cases, an aqueous electrolyte cannot be used instead of a molten one. Explain.

40.   If an electrolytic cell contained an electrolyte of an aqueous solution of aluminium nitrate, zinc sulfate, lead nitrate and nickel sulfate, list in order which metals would form at the cathode.
41.   In general, what is the voltage needed to power an electrolytic cell?

42.   What is a Faraday?
43.   List Faraday’s Laws.
« Last Edit: November 06, 2016, 08:45:46 pm by heidiii »

ice_blockie

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Re: VCE Chemistry Revision Questions
« Reply #1 on: June 09, 2008, 05:22:40 pm »
0
Oh, and if anyone wants to add some of their own, feel welcome!

Mao

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Re: VCE Chemistry Revision Questions
« Reply #2 on: June 09, 2008, 05:48:07 pm »
+2
Suggested solutions: a collaborative effort by Mao and Polky:


VCE Chemistry Unit 3: Area of Study – Chemical Analysis


Give an example of some safety procedures that should be followed during experiment X involving volumetric analysis / gravimetric analysis?
wear safety glasses
lab coat
keep acids out of reach of children xD

Suppose the actual percentage by mass of X obtained through gravimetric analysis was lower/higher than the calculated percentage. Suggest one reason how this may have come about.
Mass high: not completely dried, other impurities [that precipitated out]
Mass low: didn't filter out all the precipitate, loss some of the stuff when transferring it to the volumetric flask, didn't precipitate everything

Suppose the actual concentration of X obtained through volumetric analysis was lower/higher than the calculated percentage. Suggest one reason how this may have come about.
Conc high: washed burette with water/wrong chemical, overshot the end-point
"concentration is lower because you washed the stupid pipette with the stupid water you stupid person"
contributor to both: wrong indicator, left NaOH sit in air for too long

Explain the meaning of the term ‘primary standard’ and suggest why sodium hydroxide is not suitable for use as one.
does not react with atmosphere, known formula, abundant and cheap, relatively high molecular mass
NaOH reacts with CO2 and like to suck water out of atmosphere, hence not suitable.

Explain how sodium hydroxide can used to titrate sample X.
1. pipette an accurate aliquot of NaOH, then titrate against X [in burette]
2. pipette an accurate aliquot of X, then titrate with NaOH [in burette]

Explain why the light is pulsed in atomic absorption spectroscopy.
the light is pulsed in AAS to differentiate it from ambient light

Which wavelength of light should be chosen to analyse sample X?
shine a broad spectrum of UV-visible, then select the wavelength with maximum absorbance

Give possible reasons why compound X has a higher/lower Rf value than compound Y.
stronger adsorption/desorption to stationary/mobile phase.

Suggest why compound X has a higher/lower Rt value than compound Y.
higher Rt: attracts to stationary phase more [OR IN HPLC ITS BECAUSE ITS FATTER :D]

What is the purpose of tetramethylsilane in NMR spectroscopy?
TMS marks the 0, X marks the spot :D

How is a suitable indicator chosen for a titration?
depends on the reaction:
weak acid + strong base = phenolpthalein
weak base + strong acid = methyl orange
strong acid + strong base = methyl red
weak acid + weak base = learn to back-titrate you idiot :P

A student wanted to identify the concentration of compound X. A sample of compound X was taken and diluted in a volumetric flask. An aliquot of this diluted solution was then transferred to a conical flask. A burette was filled with compound Y. Which indicator should be added to the solution in the conical flask if X and Y were:
a) a weak acid and a weak base
b) a weak acid and a strong base
c) a strong acid and a strong base
d) a strong acid and a weak base

see above :P

Briefly explain the principles of nuclear magnetic resonance spectroscopy.
put magnet next to nucleus with nucleons spinning -> the spin aligns to the magnetic field -> the difference in energy of those against the magnetic field and those with the field is measured -> chemical shift

Briefly explain the principles of infrared spectroscopy.
shine IR -> bonds stretch/bend -> absorption

Briefly explain the principles of mass spectrometry.
blast vapourised sample with electrons -> ionises/fragments -> send down a bent tube -> depending on m/e ratio the path bends -> detector

What further experiment should be performed so that the exact concentration of compound X can be found? Consider GC, HPLC, AAS and UV Visible
GC: volatile organic
HPLC: non-volatile organic [larger ones]
AAS: metal cations
UV-visible: pretty colours [generally] xD

VCE Chemistry Unit 3: Area of Study 2 – Organic Chemical Pathways

A mixture of different hydrocarbons was found to contain compound X, Y and Z. Given that X has the lowest boiling point and Z has the highest boiling point, explain how you could collect a pure amount of substance X, Y or Z.
fractional distillation: BOIL it, then allow to cool: Z will condense first, X will be last, etc.

Explain how a bromine test can be used to determine saturation of a compound.
Alkene + bromine (brown) -> bromoalkane (colourless)

Explain how proteins can act as markers for diseases, using an example of a specific disease to illustrate your answer.
Disease -> cell burst -> protein leaks -> disease marked =]

Explain what is meant by the term ‘biochemical fuels.’
fuel produced from biological sources, such as ethanol from yeast, biodiesel from fats, biogas from cow fart, etc.

Explain why biochemical fuels are considered carbon neutral.
to make it consumes carbon
and to burn it releases carbon in to the atmosphere
so it cancels out

Explain through the use of fully balanced equations how biodiesel can be produced from oleic acid.
R-COOH + CH3OH -> R-COOCH3 + H2O
[i cbf typing out oleic acid :P]

Explain the difference in chemical properties between starch and glycogen.
glycogen has more side-branches than starch
What characteristic structure must an acid have to be classified as a 2-amino acid (α-amino acid)?

Why is the action of an enzyme often described as operating like a ‘lock and key’?
substrate fits exactly into the active site

Describe how the activity of an enzyme is affected by a temperature increase.
it may denature and coagulate the enzyme, hence there may be reduced or no reaction.

Explain the significance of the tertiary structure of an enzyme to its biological activity.
overall structure -> active site, required to be in exact shape or no catalytic function.

Explain the effects of a change of pH on the biological activity of enzymes.
denaturing as secondary structure [and tertiary structure] is affected

What is meant by the term ‘coagulation’?
posh term for "tangling"

Explain how an enzyme catalyses the reaction between compound X and Y.
lowers activation energy [THANKS MATT THE RAT] <----- unit 4 knowledge
"it takes it and then it beats it up"

What is the difference between the ‘primary’, ‘secondary’ and ‘tertiary’ structure of DNA?
Primary: single strand
Secondary: base pairing and double helix
Tertiary: histones and all the complicated proteins, further coiling.

Explain, using specific reference to the change in bonding, how DNA can replicate itself.
replicate? NOT ON COURSE KTHNX [i meant to say, i dont know :P ]

How does DNA control biochemical processes?
NOT ON COURSE!

‘A tiny change in DNA can lead to a variation in the sequence of amino acids in a protein, resulting in major health problems.’ Referring to a specific example, explain why this is the case.
wrong-code -> wrong amino acid -> stuffed up protein -> stuffed up function -> dead or very ill person

What is meant by the term ‘polymerase chain reaction’?
denature - anneal - extend
repeat 30 times = 1 billion target strands :D

Explain how the DNA fragments separate in gel electrophoresis.
the -O- on phosphate makes it charged -> apply electric field and DNA moves to the cathode
gel matrix means longer chains move through slower [more obstructions], smaller chains move faster/further

Describe the process in which a DNA profile is constructed.
sample -> PCR -> gel electrophresis -> photographic plate -> DNA profile

Explain why salicylic acid in its original form is not used as an analgesic.
it taste disgusting and irritates stomach

Define the terms ‘atom economy’ and ‘percentage yield.’
atom economy: produce as little waste as possible
percentage yield: precentage product is produced from theoretical yield
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polky

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Re: VCE Chemistry Revision Questions
« Reply #3 on: June 09, 2008, 05:56:36 pm »
+1
YEAH HIGH-5 MAO lol.

I think we missed out one:

What characteristic structure must an acid have to be classified as a 2-amino acid (α-amino acid)?
Both amine and carboxylic acid functional groups must be attached to the same carbon atom.

Explain, using specific reference to the change in bonding, how DNA can replicate itself.
Enzyme comes and "unzips" the doublestranded DNA down the middle (breaks the hydrogen bonds).  Annealing of primers, etc, alot of bio stuff. One strand is able to be replicated straight, while another has to be replicated backwards in little sections then these little sections join up together again in the end.  THIS IS ALL BIO STUFF lol.

How does DNA control biochemical processes?
Controls what proteins are made etc.  lol I really doubt we need to know this xD
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Glockmeister

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Re: VCE Chemistry Revision Questions
« Reply #4 on: June 09, 2008, 06:12:38 pm »
0
Quote
Explain how proteins can act as markers for diseases, using an example of a specific disease to illustrate your answer.
Disease -> cell burst -> protein leaks -> disease marked =]

I think you need to mention a particular protein and the associated disease. Prostate Specific Antigen in Prostate Cancer is one example
"this post is more confusing than actual chemistry.... =S" - Mao

[22:07] <robbo> i luv u Glockmeister

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<@Ahmad0> no
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Re: VCE Chemistry Revision Questions
« Reply #5 on: June 09, 2008, 06:15:11 pm »
0
Quote
Explain how proteins can act as markers for diseases, using an example of a specific disease to illustrate your answer.
Disease -> cell burst -> protein leaks -> disease marked =]

I think you need to mention a particular protein and the associated disease. Prostate Specific Antigen in Prostate Cancer is one example

Heart attack: muscle cell fail -> protein leak -> disease marked :D
Editor for ATARNotes Chemistry study guides.

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chem-nerd

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Re: VCE Chemistry Revision Questions
« Reply #6 on: June 09, 2008, 06:20:34 pm »
0
Nice work!

Explain how sodium hydroxide can used to titrate sample X.
1. pipette an accurate aliquot of NaOH, then titrate against X [in burette]
2. pipette an accurate aliquot of X, then titrate with NaOH [in burette]

1. Standardise NaOH first (cos it's a crap primary standard)
2. Pipette aliquot of NaOH, then titrate against X (in burette)

Tend not to put NaOH in burette cos it clogs it up and the lab tech will get angry

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Re: VCE Chemistry Revision Questions
« Reply #7 on: June 09, 2008, 07:11:51 pm »
0
Explain why the light is pulsed in atomic absorption spectroscopy.
the light is pulsed in AAS to differentiate it from ambient light

isnt it more to do with differentiating it from the light that the metal emits? since the atoms are absorbing those wavelengths, it makes sense that theyll eventually emit them as well as their electrons return back to ground state.
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polky

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Re: VCE Chemistry Revision Questions
« Reply #8 on: November 06, 2008, 01:02:27 pm »
0
POLKY IS HEREEEEE!

teaming up with Mao again (I think).
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Mao

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Re: VCE Chemistry Revision Questions
« Reply #9 on: November 06, 2008, 05:47:10 pm »
+2
As expected [from last time]:

Some suggested answers [that are not necessarily complete, coherent or right]
A Mandy & mostly Mao collaboration [as expected]

AREA OF STUDY 1: INDUSTRIAL CHEMISTRY

Reaction Rates
1.   What are the conditions that need to be met so that a reaction occurs?
must collide with the right orientation and enough energy to overcome the activation energy barrier

2.   What is the collision theory?
some reactions take place because the reactant particles collide
collision based reactions can achieve higher rate of reaction by either or both having higher rate of collision or the particles having higher kinetic energy

3.   What is activation energy?
energy required initially so a reaction can proceed [in uncatalysed reactions, this is the energy required to break bonds]

4.   Explain in terms of collision theory how each of the following affects the rate of reaction:
a)   Concentration b) Pressure c) Temperature d) Surface Area e) Catalyst
a) higher concentration of reactants = more particles to react = more frequent fruitful collisions = higher ROC
b) Higher pressure, the particles are closer together so more frequent collisions = more fruitful collisions = higher roc
c) temperature increase = particles move around faster = more collisions, particles have more kinetic energy = higher probability for fruitful collision = more fruitful collisions = higher ROC
d) increased surface area = more reactant particles exposed = more collisions = more frutiful = high roc
e) use of catalyst = provides alternative reaction pathway = activation energy lowered = higher proportion of collisions are considered successful = higher roc

5.   How does the reaction rate change with respect to time if the reaction is a) exothermic b) endothermic?
Exothermic reactions release heat to surrounding - RR increase
Endothermic reactions absorb heat from surrounding - RR decrease

6.   Name two ways how the rate of a reaction could be monitored.
depend on the reaction:
 - evolution of products [such as gas, coloured compound, crystals]
 - rate of consumption of reactant
 - overall pressure/colour intensity

Equilibrium Reactions
7.   What are equilibrium reactions?
dynamic reactions that goes forward as well as backward

8.   When is equilibrium reached?
rate of forward reaction = rate of backward reaction, i.e. no overall change in concentration of products or reactants

9.   Why is equilibrium said to be dynamic?
reaction is always taking place, i.e. at equilibrium the reactions do not "stop"

10.   Given the equation A + B ↔ C + D, write the equilibrium constant for the reverse reaction.


11.   Explain the effect of a catalyst on the yield of a reaction.
nothing, it allows equilibrium to be established quicker, but no effect on yield

12.   What is the difference between the concentration fraction and the equilibrium constant?
K is constant for a temperature, whereas Q [or CF] is the expression at all sorts of conditions [even when not at equilibrium]

13.    When the concentration is smaller than the equilibrium constant, what will be the net reaction?
net forward

14.   When the concentration is larger than the equilibrium constant, what will be the net reaction?
net backward

15.   What does the magnitude of K tell us about an equilibrium reaction?
larger K -- most reactants are converted to products
small K -- most reactants remain unreacted

16.   How does K change with respect to time when the reaction is a) exothermic b) endothermic?
in VCELand, temperature is kept constant, hence K does not change with respect to time.

17.   State Le Chatelier’s principle.
A equilibrium system will partially oppose a change done to it.

18.   Using Le Chatelier’s principle, explain how each of the following affects the position of equilibrium:
a) addition of reactants or products b) changing the temperature
c) changing the pressure or volume d) dilution of system e) addition of catalysts  
f) addition of inert gases g) addition of water if water is also a reactant
a) add reactants=net forward, add products = net backwards
b) change in temp, assume increase in temp, if forward reaction is exo, there is a net backwards reaction, if endo, net forwards
c) changing pressure or volume, if pressure increase, reaction that produces less particles is favoured, vice versa
d) dilution is increase in volume? net reaction towards the side that produces more particles
e) catalyst = no change
f) no change
g) net forward

19.   Explain why pure water has a pH of 7. AT 25 DEGREES ONLY!
the H+ concentration at 25 degrees is M

20.   When the temperature is increased, what is the effect on the pH of pure water?
decrease. self ionisation of water is endothermic

21.   Give a typical equilibrium of a weak acid.

Ka is small

22.   Define a strong acid in terms of equilibrium.
Ka is large, i.e. most of the reactants are converted to products.

23.   List the following acids from weakest to strongest: hydrofluoric acid, ethanoic acid, boric acid, nitrous acid, and lactic acid.
Boric < ethanoic < lactic < nitrous < hydrofluoric

24.   Define percent ionisation.
the percentage of reactants that reacted to products [ionised] in an acid dissociation reaction.

25.   What is a buffer?
a weak acid and its conjugate base [or a weak base and its conjugate acid] that can compensate for addition of base and acid to a system, hence keeping the pH roughly constant.

Waste Management
26.   Define atom economy.
percentage of atoms in the reactants that end up as desired product

27.   Define ‘waste management’ and list some ways how waste can be ‘managed.’ <---can't be bothered.
Minimisation of waste [products/energy] or responsible disposal of waste.


Industrial production of a chemical
28.   Give the formula and name of the chemical you have studied this year.
Sulfuric acid, H2SO4

29.   Give the equilibrium reaction in the industrial production of your chemical and state whether it is exothermic or endothermic.
[tes]2SO_2(g)+2O_2(g)\leftrightharpoons 2SO_3(g)[/tex], exothermic

30.   List the conditions of temperature and pressure that would theoretically maximise yield and rate of the industrial production of your chemical.
high pressure, low temperature

31.   List the conditions of temperature and pressure that are actually used in the industrial production of your chemical explaining the difference, if any, between your answer to Q 30 and Q31.
450 degrees celsius [moderate temperature]
1 atm pressure
rate of reaction is improved by use of catalysts [in catalyst beds so to maximise surface area]
equilibrium yield is improved by use of excess reactants, continual removal of product and cycling [3 times through the reaction chamber]
the yield and ROR become good enough that high pressure is not necessary.

32.   Write an equation where your chemical is a reactant.


33.   Write an equation where your chemical is a product.


34.   List 3 uses of your industrial chemical.
production of fertiliser
electrolyte in car batteries
production of dyes

35.   Explain how the principles of green chemistry apply to the industrial production of your chemical.
the only product is the desired product. therefore ATOMIC ECONOMY TO THE MAX.

36.   List two health and safety procedures that are followed in the industrial production of your chemical.
reaction chambers are sealed [as gases are toxic]
safe handling of reactants/chemicals, MSDS, responsible disposal, spillage plans, earthquake survival plans, alien domination plans, terrorist strike plans, experiment on the chickens plan, world domination plans...

37.   Explain how waste management is applied to the industrial production of your chemical.
excess heat is used to power other processes/generate electricity.

AREA OF STUDY 2: SUPPLYING AND USING ENERGY

Energy Sources
38.   Explain the difference between the terms ‘renewable’ energy sources and ‘sustainable’ energy sources’.
Renewable - can be reproduced within a reasonable timeframe
Sustainable - can be reproduced as an ongoing process that meets the demand of modern day society

39.   List 5 renewable and 3 non-renewable energy sources.
Renewable - biochemical fuels, solar, wind, tidal, geothermal
non-renewable - fossil fuels, natural gas, nuclear

40.   Which energy sources currently do not commercially operate in Australia? Give reasons for your answer.
Nuclear, due to security and waste management concerns.

Thermochemistry
41.   What is an energy profile?
Change in enthalpy of a reaction

42.   What is an endothermic reaction? What is an exothermic reaction?
Endothermic: net absorption of energy from surroundings
Exothermic: net release of energy to surroundings

43.   Draw a typical energy profile for an exothermic and an endothermic reaction.
Code: [Select]
|    _   exothermic
|   / \
|__/   \
|       \
|        --
|____________
Code: [Select]
|    _   endothermic
|   / \_____
|__/  
|    
|      
|____________

44.   Define enthalpy in terms of bonding and energy.
Strong bonds - small chemical energy, low enthalpy
Weak bonds - high chemical energy, high enthalpy

45.   Name three important parts of a thermochemical equation.
balanced equation, states of chemicals, coefficients, .....?

46.   Explain the difference between heat capacity and heat of combustion.
heat capacity is the energy required to raise one gram of the said material by one degree
heat of combustion is the energy released when one gram of the said material undergoes complete combustion

47.   Explain why the heats of combustion of foods are given in kJ per gram rather than kJ per mol.
foods do not have a known chemical formula [it is a mixture of many different compounds], hence there is no definite molar mass.

48.   Explain the function of a calorimeter.
measures the change in energy

49.   Give the names of two different types of calorimeters and describe their respective uses.
Solution calorimeter - measures change in energy of reactions between aqueous/solid species.
Bomb calorimeter - measures change in energy of more energetic reactions such as combustion in a sealed clay chamber.

50.   Why do calorimeters need to be calibrated?
Allow interpretation of data

51.   Name three ways how a calorimeter can be calibrated.
Pass a current with known voltage for a certain amount of time
Reaction of accurate mass and
??Use of specific heat capacities??

52.   Name two ways how the actual value of the calibration factor could be higher than the calculated value.
not enough water
inaccurate measurements

53.   Name two ways how the actual value of the calibration factor could be lower than the calculated value.
too much water
inaccuratae measurements

54.   Name three formulas used in thermochemistry.
???

Electrochemistry
55.   What is a redox reaction?
electron transfer

56.   Define oxidation, reduction, oxidant and reductant.
Oxidant causes oxidation (loss of electron) and is itself reduced (gain of electron).
vice versa

57.   State the rules for oxidation numbers.
elemental allotropes all = 0
H = +1
O = -2
sum of oxidation numbers in an ion = its charge

58.   How do you write a balanced half equation?
KOHES(B)

59.   What is a galvanic cell?
spontaneous redox reaction occuring in two separate half cells with electrons moving through an external circuit and a salt bridge.

60.   Explain the function of a salt bridge.
keep the two cells electro-neutral and "completes the circuit"

61.   Why are the half cells separated in a galvanic cell?
to allow the energy possessed by the moving electrons to be harnessed [battery]

62.   Assign polarities to the cathode and the anode.
Cathode = +
Anode = -

63.   Explain the properties that an electrode must have.
Conductive

64.   Explain the choice of electrode if
a)   one member of the conjugate pair in a half cell is a metal
the metal

b)   no metal is present
inert [graphite or platinum]

c)   one member of the conjugate pair is a gas
inert [assuming the other is aqueous]

65.   Explain how the electrochemical series can be used to predict redox reactions.
strongest oxidant react with strongest reductant

66.   Define potential difference.
difference in E-nought

67.   List three reasons why a predicted redox reaction does not occur.
non-standard conditions
rate of reaction is too slow
side reactions

68.   Explain the difference between a primary and a secondary cell.
secondary cells can be recharged [products of discharge remain on the electrode]
primary cells cannot be recharged [products of discharge migrate away from the electrode]

69.   Explain why fuel cells are considered more efficient than power stations.
direct conversion of chemical energy to electrical is more efficient than the chemical -> thermal -> thermal -> mechanical -> electrical

70.   Why are secondary cells able to be recharged but not primary cells?
see 68 brackets.

71.   How do you recharge a secondary cell?
apply a voltage in reverse direction of discharge at greater magnitude than recharge
THEN MAGIKS

72.   What is the difference between a fuel cell and primary/secondary cells?
fuel cell supply energy so long as fuel is fed. electrochemical cells eventually run out of reactants/establish equilibrium and "go flat".

73.   What is electrolysis?
non-sponaneous redox reactions by applying a voltage

74.   Compare the similarities and differences between an electrolytic cell and a galvanic cell.
electrolytic cell is a galvanic cell in reverse, with the voltmeter replaced by a battery placed in reverse orientation

75.   Explain why the products of an electrolytic cell must not come into contact.
the products of electrolytic cells will spontaneously react

76.   In some cases, an aqueous electrolyte cannot be used instead of a molten one. Explain.
water can act as oxidant and reductant, hence in some cases where water is a stronger oxidant/reductant than the reactant, water must not be present, hence molten reactants [or dissolved in cryolite or other solvents] are required as aqueous solutions are not adequate

77.   If an electrolytic cell contained an electrolyte of an aqueous solution of aluminium nitrate, zinc sulfate, lead nitrate and nickel sulfate, list in order which metals would form at the cathode.
lead->nickel->zinc->hydrogen bubblez

78.   In general, what is the voltage needed to power an electrolytic cell?
greater than the potential difference between the two standard cells

79.   What is a Faraday?
1 mole of electron

80.   List Faraday’s Laws.
???
Editor for ATARNotes Chemistry study guides.

VCE 2008 | Monash BSc (Chem., Appl. Math.) 2009-2011 | UoM BScHon (Chem.) 2012 | UoM PhD (Chem.) 2013-2015

ice_blockie

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Re: VCE Chemistry Revision Questions
« Reply #10 on: November 06, 2008, 06:24:36 pm »
0
16.   How does K change with respect to time when the reaction is a) exothermic b) endothermic?
in VCELand, temperature is kept constant, hence K does not change with respect to time.

*Hmmm* - I don't even know why I put this in....

54.   Name three formulas used in thermochemistry.
???

Badly worded question - I meant , , and

80.   List Faraday’s Laws.
???

again dodgy question by me...i meant and

onlyfknhuman

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Re: VCE Chemistry Revision Questions
« Reply #11 on: November 08, 2008, 12:45:02 pm »
0
16.   How does K change with respect to time when the reaction is a) exothermic b) endothermic?
in VCELand, temperature is kept constant, hence K does not change with respect to time.

*Hmmm* - I don't even know why I put this in....

54.   Name three formulas used in thermochemistry.
???

Badly worded question - I meant , , and

80.   List Faraday’s Laws.
???

again dodgy question by me...i meant and

Nice list, btw Whats E = SHC x m x T

Lol is that the same as E= mcd x delta T , where m = mass of some solution and c = the liquid constant water = 4.18 and d = density

ps.Anyone wanna do a revision list for detailed study eg. H2S04, i dont mind doing it if asked, but i'll be pretty shoddy
« Last Edit: November 08, 2008, 07:12:16 pm by onlyfknhuman »
English - VCD - Methods - Physics - Chemistry - Art - Japanese

give me the name list of all the hot chicks u know  ;)

Antonyant

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Re: VCE Chemistry Revision Questions
« Reply #12 on: November 12, 2008, 08:19:25 pm »
0
mao i love u.... thanks
the boi who thinks not enough.. meh

MaJezTiK

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Re: VCE Chemistry Revision Questions
« Reply #13 on: November 12, 2008, 10:10:55 pm »
0
63. They must also be inert?

Lol dont mind me im so owned for chem after my A for midyear ive given up lol but only tying since its my last exam now

Toothpaste

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Re: VCE Chemistry Revision Questions
« Reply #14 on: November 12, 2008, 10:13:31 pm »
0
16.   How does K change with respect to time when the reaction is a) exothermic b) endothermic?
in VCELand, temperature is kept constant, hence K does not change with respect to time.

*Hmmm* - I don't even know why I put this in....

54.   Name three formulas used in thermochemistry.
???

Badly worded question - I meant , , and

80.   List Faraday’s Laws.
???

again dodgy question by me...i meant and

Nice list, btw Whats E = SHC x m x T

specific heat capacity = SHC

i.e. E(energy) = 4.18 (water) * mass * Temp

EDIT: didn't read properly, I mean: yes.