criticise my syllabus summary! (1 Viewer)
- Thread starter .ben
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pLuvia
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Explain what a displacement reaction is, and say:
A displacement reaction is a reaction where electrons are transferred as metals are oxidised or lose electrons to become metal ions and metal ions gain electrons or reduce to because a metal atoms.
And maybe give an example
A displacement reaction is a reaction where electrons are transferred as metals are oxidised or lose electrons to become metal ions and metal ions gain electrons or reduce to because a metal atoms.
And maybe give an example
The excel one is quite average really, it's very brief in alot of the modules, but I'm not sure about pathways, haven't seen it before. I would highly recommend Conquering Chemistry and Chemistry Contexts 2, which I currently have and use for my summaries.
By the way, your dotpoint summaries are fine; I as just curious as to where you got your info from.
By the way, your dotpoint summaries are fine; I as just curious as to where you got your info from.
P
pLuvia
Guest
I use Conquering Chemistry. Try and get Conquering Chemistry it's really good, organised etc
P
pLuvia
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Macquarie is recommended over excel, but get the CCs
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4th Edition CC is the bomb.pLuvia said:Macquarie is recommended over excel, but get the CCs
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It's worth it. Although Context is pretty good too..ben said:
I bought the 4th Edition Preliminary CC today at 25% discount because the cover was slightly creased. Moral: Crease cover for discount.
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I'm tutoring both Prelim and HSC, and I never had a proper Prelim textbook. (I used Excel which was utterly, utterly hopeless).ben said:
nuclear chemistry bit:
Distinguish between stable and radioactive isotopes and describe the conditions under which a nucleus is unstable
An isotope is one of two or more species of an atom having the same atomic number, hence constituting the same element, however possessing a different mass number. In other words, isotopes of an element differ from the original element by having a different number of neutrons. Any isotope may be represented by:
Where ‘A’ represents mass number or the number of protons and neutrons and ‘Z” represents atomic number which is the number of protons.
A radioactive isotope is an unstable isotope which emits radiation.
Instability in atoms is generally defined as a neutron to proton ratio which deviates significantly from the ‘standard’ ratios. These ‘standard’ ratios include an N ratio of ≈ 1:1 for the first 20 elements and an N ratio of ≈ 1.6:1 for all elements up of 82 after that. After 82 however, the nucleus can never be stable as it has exited the range of the number of protons and neutrons the nucleus can stably hold.
More specifically, three potential cases for instability can arise. These are: too many protons for the number of neutrons (proton excess), too many neutrons for the number of protons (neutron excess) and finally too many protons and neutrons altogether (nucleon excess).
In the case of a proton excess, a proton is converted into a neutron resulting in the emission of radiation in the form of a +β ray. The β rays released are quite ionising meaning they cannot travel far through space; however they are more penetrating than α rays. This process is termed positive beta decay. An equation demonstrates this process:
11p * 10n + 0+1β
In the case of neutron excess, a neutron is converted into a proton resulting in the emission of radiation in the form of a –β ray. This process is termed negative beta decay. An equation demonstrates this process:
10n * 11p + 0-1β
In the case of a nucleon excess, the nucleus ejects 2 neutrons and 2 protons which exit in the form of a helium nucleus. Along with this it also releases an α ray which are very ionising and thus cannot travel very far through space. α rays can generally be stopped by a piece of paper. This process is termed alpha decay. An equation demonstrates this process:
22286Rn * 21884Po + 42He
A situation of an excited nucleus generally exists after the ejection of nucleons from a nucleus. This excited neutron then proceeds to de-excite/relax itself by releasing γ rays which are visible photons. These visible photons cannot be represented by equations so usually light or energy is written instead. γ rays are not very ionising, thus giving them the ability to travel quite far through space. Lead is required to stop it.
Note well that nuclear reactions involve 107 times more energy than chemical reactions and occur at the sub-atomic level, meaning it constitutes mass changes. Also, when balancing nuclear equations make sure the atomic and mass numbers add up to equal on both sides.
Describe how transuranic elements are produced
Transuranic elements are elements with atomic numbers greater than 92 (Z>92) or that of uranium on the periodic table.
The general method of producing transuranic elements is to bombard nuclei with subatomic particles such as neutrons or alpha particles. Two main devices are used to produce transuranic elements, the particle accelerator and the nuclear reactor.
Particle accelerators used to produce transuranic elements operate on the principle of firing accelerated particles into a target. This can be done in two ways, firstly by accelerating the particle in a spiral (cyclotron) or in a straight line (linear accelerator/synchrotron). The isotopes produced from particle accelerators are generally, neutron deficient which means they emit positive beta particles.
A nuclear reactor is another device which can be used to create transuranic elements. These provide a safe environment where larger nuclei can be bombarded with neutrons causing nuclear fission and a neutron flux. Because of this, all isotopes produced from nuclear reactors are neutron rich making them negative beta emitters.
Describe how commercial radioisotopes are produced
Both transuranic elements and commercial isotopes are produced via methods mentioned above. The only difference between production of the two is the fact that when chemists are producing commercial isotopes, there is a definite objective, e.g. to produce a quantity of technetium-99m or cobalt-60 etc. However, when producing transuranic elements, the objective is more experimental with no definite objectives, e.g. trying to produce a new unknown element
Identify instruments and processes that can be used to detect radiation
There are three types of radiation produced from the decay of radioactive substances alpha, beta and gamma particles. To understand we detect these types of radiation we firstly must review the process of distinguishing them. This can be done by observing either their respective penetrating powers or their paths in a magnetic field. A diagram below demonstrates the penetrating powers of the three types of radiation.
From the diagram, it can be seen that alpha and beta radiation are stopped by relatively thin substances with a piece of paper and 3mm of aluminium respectively. We can conclude from this that alpha and beta radiation is highly ionising (high energy). On the other hand, gamma radiation cannot be stopped, only its intensity halved by a thick lead wall. Thus many lead walls are required to reduce the effects of gamma rays to a safe level.
Another method of differentiating between the three types of radiation is by running them through a magnetic field as shown below.
As the source emits the radiation, the alpha particles bend toward the top, attracted to the negative plate, while the beta particles bend toward the bottom, attracted to the positive plate. Gamma rays travel straight through, unaffected by the plates. The result is recorded on a photographic plate.
In exploiting different characteristics of these types of particles and rays, techniques have been developed to detect radiation. There are a couple of main processes/instruments which can be used to detect radiation; these include the Geiger-Muller tube, an electroscope, a cloud chamber and a scintillation counter. The scintillation counter specialises in detecting low ionising radiation.
The Geiger-Muller (GM) tube and counter is a device which exploits the ionisation of radiation to detect particles. As radiation enters a sealed cylindrical metal tube, it comes into contact with argon gas at low pressure levels. This contact precipitates a reaction producing argon ions and electrons, which move to oppositely charged electrodes. Once this process completes, a small electrical pulse is attained and amplified to generate a current which powers a pulse converter.
The scintillation counter is able to detect weak emissions. It works with a radioactive nucleus relaxing and thus emitting excess energy which is transferred to a fluorescent solute molecule. This molecule then gives off light which can be detected by photocells which produce a pulse of electrical current when hit by the light.
Identify one use of a named radioisotope: - in industry - in medicine
One radioisotope used in medicine is Technetium-99m. It can be utilised for gamma ray imaging through radioactive tracing of vital organs.
One radioisotope used in industry is Cobalt-60. It can be utilised for sterilising medical apparatus.
Distinguish between stable and radioactive isotopes and describe the conditions under which a nucleus is unstable
An isotope is one of two or more species of an atom having the same atomic number, hence constituting the same element, however possessing a different mass number. In other words, isotopes of an element differ from the original element by having a different number of neutrons. Any isotope may be represented by:
Where ‘A’ represents mass number or the number of protons and neutrons and ‘Z” represents atomic number which is the number of protons.
A radioactive isotope is an unstable isotope which emits radiation.
Instability in atoms is generally defined as a neutron to proton ratio which deviates significantly from the ‘standard’ ratios. These ‘standard’ ratios include an N
ratio of ≈ 1:1 for the first 20 elements and an N ratio of ≈ 1.6:1 for all elements up of 82 after that. After 82 however, the nucleus can never be stable as it has exited the range of the number of protons and neutrons the nucleus can stably hold. More specifically, three potential cases for instability can arise. These are: too many protons for the number of neutrons (proton excess), too many neutrons for the number of protons (neutron excess) and finally too many protons and neutrons altogether (nucleon excess).
In the case of a proton excess, a proton is converted into a neutron resulting in the emission of radiation in the form of a +β ray. The β rays released are quite ionising meaning they cannot travel far through space; however they are more penetrating than α rays. This process is termed positive beta decay. An equation demonstrates this process:
11p * 10n + 0+1β
In the case of neutron excess, a neutron is converted into a proton resulting in the emission of radiation in the form of a –β ray. This process is termed negative beta decay. An equation demonstrates this process:
10n * 11p + 0-1β
In the case of a nucleon excess, the nucleus ejects 2 neutrons and 2 protons which exit in the form of a helium nucleus. Along with this it also releases an α ray which are very ionising and thus cannot travel very far through space. α rays can generally be stopped by a piece of paper. This process is termed alpha decay. An equation demonstrates this process:
22286Rn * 21884Po + 42He
A situation of an excited nucleus generally exists after the ejection of nucleons from a nucleus. This excited neutron then proceeds to de-excite/relax itself by releasing γ rays which are visible photons. These visible photons cannot be represented by equations so usually light or energy is written instead. γ rays are not very ionising, thus giving them the ability to travel quite far through space. Lead is required to stop it.
Note well that nuclear reactions involve 107 times more energy than chemical reactions and occur at the sub-atomic level, meaning it constitutes mass changes. Also, when balancing nuclear equations make sure the atomic and mass numbers add up to equal on both sides.
Describe how transuranic elements are produced
Transuranic elements are elements with atomic numbers greater than 92 (Z>92) or that of uranium on the periodic table.
The general method of producing transuranic elements is to bombard nuclei with subatomic particles such as neutrons or alpha particles. Two main devices are used to produce transuranic elements, the particle accelerator and the nuclear reactor.
Particle accelerators used to produce transuranic elements operate on the principle of firing accelerated particles into a target. This can be done in two ways, firstly by accelerating the particle in a spiral (cyclotron) or in a straight line (linear accelerator/synchrotron). The isotopes produced from particle accelerators are generally, neutron deficient which means they emit positive beta particles.
A nuclear reactor is another device which can be used to create transuranic elements. These provide a safe environment where larger nuclei can be bombarded with neutrons causing nuclear fission and a neutron flux. Because of this, all isotopes produced from nuclear reactors are neutron rich making them negative beta emitters.
Describe how commercial radioisotopes are produced
Both transuranic elements and commercial isotopes are produced via methods mentioned above. The only difference between production of the two is the fact that when chemists are producing commercial isotopes, there is a definite objective, e.g. to produce a quantity of technetium-99m or cobalt-60 etc. However, when producing transuranic elements, the objective is more experimental with no definite objectives, e.g. trying to produce a new unknown element
Identify instruments and processes that can be used to detect radiation
There are three types of radiation produced from the decay of radioactive substances alpha, beta and gamma particles. To understand we detect these types of radiation we firstly must review the process of distinguishing them. This can be done by observing either their respective penetrating powers or their paths in a magnetic field. A diagram below demonstrates the penetrating powers of the three types of radiation.
From the diagram, it can be seen that alpha and beta radiation are stopped by relatively thin substances with a piece of paper and 3mm of aluminium respectively. We can conclude from this that alpha and beta radiation is highly ionising (high energy). On the other hand, gamma radiation cannot be stopped, only its intensity halved by a thick lead wall. Thus many lead walls are required to reduce the effects of gamma rays to a safe level.
Another method of differentiating between the three types of radiation is by running them through a magnetic field as shown below.
As the source emits the radiation, the alpha particles bend toward the top, attracted to the negative plate, while the beta particles bend toward the bottom, attracted to the positive plate. Gamma rays travel straight through, unaffected by the plates. The result is recorded on a photographic plate.
In exploiting different characteristics of these types of particles and rays, techniques have been developed to detect radiation. There are a couple of main processes/instruments which can be used to detect radiation; these include the Geiger-Muller tube, an electroscope, a cloud chamber and a scintillation counter. The scintillation counter specialises in detecting low ionising radiation.
The Geiger-Muller (GM) tube and counter is a device which exploits the ionisation of radiation to detect particles. As radiation enters a sealed cylindrical metal tube, it comes into contact with argon gas at low pressure levels. This contact precipitates a reaction producing argon ions and electrons, which move to oppositely charged electrodes. Once this process completes, a small electrical pulse is attained and amplified to generate a current which powers a pulse converter.
The scintillation counter is able to detect weak emissions. It works with a radioactive nucleus relaxing and thus emitting excess energy which is transferred to a fluorescent solute molecule. This molecule then gives off light which can be detected by photocells which produce a pulse of electrical current when hit by the light.
Identify one use of a named radioisotope: - in industry - in medicine
One radioisotope used in medicine is Technetium-99m. It can be utilised for gamma ray imaging through radioactive tracing of vital organs.
One radioisotope used in industry is Cobalt-60. It can be utilised for sterilising medical apparatus.
ethanol bit:
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Describe the dehydration of ethanol to ethylene and identify the need for a catalyst in this process and the catalyst used
Ethanol is a molecule of ethane with one hydrogen atom substituted for an OH hydroxy functional group. It is useful substance and has a large potential for future use. Presently however, one of its major uses is its ability to be converted into ethylene. This is achieved through the process known as dehydration and requires an acid catalyst. During dehydration, ethanol is heated to approximately 180oC in the presence of a concentrated sulphuric or phosphoric acid. The end result is the formation of ethylene and water, the latter of which can be either absorbed by the acid or distilled out. An equation below demonstrates this process:
C2H5OH(l) * C2H4(g) + H2O(l)
Describe the addition of water to ethylene resulting in the production of ethanol and identify the need for a catalyst in this process and the catalyst used
While there are two ways of producing ethene from ethanol, by fermentation of sugars or by the hydration of ethanol, with the latter process being favoured due to its economic savings. The hydration of ethylene is the exact opposite of the process used to make ethylene from ethanol, dehydration. Firstly, it involves the combining of ethylene with dilute sulphuric acid which creates a mixture of ethylene and ethyl hydrogen sulphate, which on contact with water, undergoes hydrolysis yields the desired product, ethanol. A simplified equation of this process is given below:
C2H4(g) + H2O(l) * C2H5OH(l)
Describe and account for the many uses of ethanol as a solvent for polar and non-polar substances
As mentioned above, ethanol is basically a molecule of ethane with an OH functional group replacing a hydrogen atom. The structural formula for ethanol is given below:
While the C-H bonding on the left hand side of the molecule causes dispersion forces, the OH hydroxy functional group is responsible for generating dipoles which lead to hydrogen bonding on the right hand side. This creates both a polar and non-polar molecule of ethanol which is extremely powerful if used as a solvent as it can dissolve both polar and non-polar solutes.
Outline the use of ethanol as a fuel and explain why it can be called a renewable resource
Currently, petrol is the main fuel (with ethanol used as an additive of 10-20%) used for transportation globally, however, with it being a non-renewable resource, ethanol has major potential to be the dominant fuel of the future. One major benefit in support of this fact lies in its ability to be produced and used over an indefinite period of time. This feature of ethanol classifies it as a biomass fuel. Biomass being organic products produced from photosynthesis allows these fuels to be spawned indefinitely meaning an unlimited supply, making them renewable resources.
Describe conditions under which fermentation of sugars is promoted
Favourable conditions for the fermentation of sugars include on ambient temperature of approximately 30oC-40oC and a suitable micro-organism producing an enzyme which catalyses the chemical reactions required for fermentation. Sometimes different micro-organisms require different conditions under which to operate effectively.
Summarise the chemistry of the fermentation process
Using the fermentation of sugars into ethanol as an example, an exploration can be undertaken into the chemistry of the fermentation process.
C6H12O6(aq) * 2CH3CH2OH(aq) + 2CO2(g)
In using yeast (a fungus) as a ‘starter’ for this reaction, we combine it with glucose in an anaerobic environment effectively allow to multiply through its enzymes which catalyse the decomposition of the glucose. This in turn produces ethanol and carbon dioxide gas. Because the products are directly combined with the yeast in a single solution, the concentration of the ethanol cannot be allowed to rise above 15%, otherwise the yeast will be poisoned, thus ending the fermentation process.
Define the molar heat of combustion of a compound and calculate the value for ethanol from first-hand data
Assess the potential of ethanol as an alternative fuel and discuss the advantages and disadvantages of its use
Identify the IUPAC nomenclature for straight-chained alkanols from C1 to C8
The IUPAC nomenclature for straight chained alkanols from C1 to C8 is similar to that of all naming in carbon chemistry. Since alkanols are basically saturated hydrocarbons with are hydrogen atoms replaced by an OH hydroxy functional group, they are named in the exact same way as alkanes except with an ‘ol’ suffix. Examples include:
C1 – Methanol
C2 – Ethanol
C3 – Propanol
=================================================
Describe the dehydration of ethanol to ethylene and identify the need for a catalyst in this process and the catalyst used
Ethanol is a molecule of ethane with one hydrogen atom substituted for an OH hydroxy functional group. It is useful substance and has a large potential for future use. Presently however, one of its major uses is its ability to be converted into ethylene. This is achieved through the process known as dehydration and requires an acid catalyst. During dehydration, ethanol is heated to approximately 180oC in the presence of a concentrated sulphuric or phosphoric acid. The end result is the formation of ethylene and water, the latter of which can be either absorbed by the acid or distilled out. An equation below demonstrates this process:
C2H5OH(l) * C2H4(g) + H2O(l)
Describe the addition of water to ethylene resulting in the production of ethanol and identify the need for a catalyst in this process and the catalyst used
While there are two ways of producing ethene from ethanol, by fermentation of sugars or by the hydration of ethanol, with the latter process being favoured due to its economic savings. The hydration of ethylene is the exact opposite of the process used to make ethylene from ethanol, dehydration. Firstly, it involves the combining of ethylene with dilute sulphuric acid which creates a mixture of ethylene and ethyl hydrogen sulphate, which on contact with water, undergoes hydrolysis yields the desired product, ethanol. A simplified equation of this process is given below:
C2H4(g) + H2O(l) * C2H5OH(l)
Describe and account for the many uses of ethanol as a solvent for polar and non-polar substances
As mentioned above, ethanol is basically a molecule of ethane with an OH functional group replacing a hydrogen atom. The structural formula for ethanol is given below:
While the C-H bonding on the left hand side of the molecule causes dispersion forces, the OH hydroxy functional group is responsible for generating dipoles which lead to hydrogen bonding on the right hand side. This creates both a polar and non-polar molecule of ethanol which is extremely powerful if used as a solvent as it can dissolve both polar and non-polar solutes.
Outline the use of ethanol as a fuel and explain why it can be called a renewable resource
Currently, petrol is the main fuel (with ethanol used as an additive of 10-20%) used for transportation globally, however, with it being a non-renewable resource, ethanol has major potential to be the dominant fuel of the future. One major benefit in support of this fact lies in its ability to be produced and used over an indefinite period of time. This feature of ethanol classifies it as a biomass fuel. Biomass being organic products produced from photosynthesis allows these fuels to be spawned indefinitely meaning an unlimited supply, making them renewable resources.
Describe conditions under which fermentation of sugars is promoted
Favourable conditions for the fermentation of sugars include on ambient temperature of approximately 30oC-40oC and a suitable micro-organism producing an enzyme which catalyses the chemical reactions required for fermentation. Sometimes different micro-organisms require different conditions under which to operate effectively.
Summarise the chemistry of the fermentation process
Using the fermentation of sugars into ethanol as an example, an exploration can be undertaken into the chemistry of the fermentation process.
C6H12O6(aq) * 2CH3CH2OH(aq) + 2CO2(g)
In using yeast (a fungus) as a ‘starter’ for this reaction, we combine it with glucose in an anaerobic environment effectively allow to multiply through its enzymes which catalyse the decomposition of the glucose. This in turn produces ethanol and carbon dioxide gas. Because the products are directly combined with the yeast in a single solution, the concentration of the ethanol cannot be allowed to rise above 15%, otherwise the yeast will be poisoned, thus ending the fermentation process.
Define the molar heat of combustion of a compound and calculate the value for ethanol from first-hand data
Assess the potential of ethanol as an alternative fuel and discuss the advantages and disadvantages of its use
Identify the IUPAC nomenclature for straight-chained alkanols from C1 to C8
The IUPAC nomenclature for straight chained alkanols from C1 to C8 is similar to that of all naming in carbon chemistry. Since alkanols are basically saturated hydrocarbons with are hydrogen atoms replaced by an OH hydroxy functional group, they are named in the exact same way as alkanes except with an ‘ol’ suffix. Examples include:
C1 – Methanol
C2 – Ethanol
C3 – Propanol
P
pLuvia
Guest
Distinguish between stable and radioactive isotopes and describe the conditions under which a nucleus is unstable
An isotope is unstable when the atomic number is greater than 83 and the ration of neutrons to protons is out of the zone of stability.
Describe how transuranic elements are produced
Transuranic elements can also be made by nuclear fission not occuring, (non fissile) instead it splits to form a new element. And this new element may also rapidly decay to another new element
Identify instruments and processes that can be used to detect radiation
Also photographic film, whereby the worker working under radiation wears a radiation badge (with photographic film) where it will darken which is a measure of how much radiation the worker has been exposed to
An isotope is unstable when the atomic number is greater than 83 and the ration of neutrons to protons is out of the zone of stability.
Describe how transuranic elements are produced
Transuranic elements can also be made by nuclear fission not occuring, (non fissile) instead it splits to form a new element. And this new element may also rapidly decay to another new element
Identify instruments and processes that can be used to detect radiation
Also photographic film, whereby the worker working under radiation wears a radiation badge (with photographic film) where it will darken which is a measure of how much radiation the worker has been exposed to