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Hsc Marathon 2009 - Chemistry (6 Viewers)

Sarah182

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aa .... i finished my chem half yearly last thursday, have fun studyin

p.s. my chem teacher pulled half the multiple choice questions from the 2008 HSC paper!
Bahaha you should have flogged it then.


This thread has been a bit dead so here is a new question:
Assess the impact of the recent development of a named biopolymer on society and the environment.
 

Kaatie

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biopol's uses are - surgical applications
- biodegradable carriers for long-term dosage of drugs, medicines, insecticides, herbicides or fertilisers
- disposable containers for shampoo/conditioner
- disposable items such as razors, rubbish bags, disposable nappies, fast food utensils and paper plates

deduce whether the following salts are acidic, basic or neutral and justify your decision
- sodium carbonate
- potassium sulfate
- ammonium nitrate
 

gigglinJess

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deduce whether the following salts are acidic, basic or neutral and justify your decision
- sodium carbonate
- potassium sulfate
- ammonium nitrate
sodium carbonate - basic (strong base, weak acid)

potassium carbonate - basic (strong base, weak acid)

ammonium nitrate - acidic (weak base, strong acid)

Q Define the following terms, in reference to titration.
- standard solution
- primary standard solution
- secondary standard solution
- equivalance point
- end point
 

kwabon

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sodium carbonate - basic (strong base, weak acid)

potassium carbonate - basic (strong base, weak acid)

ammonium nitrate - acidic (weak base, strong acid)

Q Define the following terms, in reference to titration.
- standard solution
- primary standard solution
- secondary standard solution
- equivalance point
- end point
hate titration

Volumetric analysis requires that one solution must have an accurately known concentration. this solution is called the standard solution

primary standard solution is a solution of high purity and stability that it can be used to prepare a solution of accurately known concentration.

secondary standard solution are solutions whose concentrations have been determined using primary standard

equivalence point is when the number of moles of H+ ions and OH- ions are equal.

end point is when the solution just changes colour.


Question: define le chateliers principle and describe factors that might affect the equilibrium.
 

GUSSSSSSSSSSSSS

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sodium carbonate - basic (strong base, weak acid)

potassium carbonate - basic (strong base, weak acid)

ammonium nitrate - acidic (weak base, strong acid)

tbh i wud give this either 0 or 1 marks

the justification in no way fits ur answer

it might have been just because ur typing it up on the internet
but as some advice that justification is worthless..=S
 

pman

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Le chateliers principle= a soln tries to find equilibrium, adding a substanc ewill drive equation to the other side (i no, badly worded)


Question, what is the elctrical potential of Zinc and Magnesium
 

kwabon

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Le chateliers principle= a soln tries to find equilibrium, adding a substanc ewill drive equation to the other side (i no, badly worded)


Question, what is the elctrical potential of Zinc and Magnesium
u mean EMF dont u??
oh well

cant be bothered to show working
will just say that zinc will be the oxidant and the magnesium will be the reductant

1.6 V, i think is the answer


Question: identify natural and industrial sources of sulfur dioxide and nitrous oxides
 

bayan92

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Question: identify natural and industrial sources of sulfur dioxide and nitrous oxides
ANSWER: Oxides of sulfur often stem from the combustion and decomposition of organic matter and volcanoes – naturally and combustion of fossil fuels, metal smelters, incineration of garbage, petroleum refineries and other industry – artificially. As for oxides of nitrogen, they are formed naturally by the actions of certain bacteria in soils and also through the formation of lightening when N reacts with to create oxides of nitrogen. Synthetically they are formed by use of nitrogen rich fertilizers by humans and from exhausts of sites of combustion (both stationary and moving engines).



QUESTION: Assess the use of neutralisation reactions as a safety measure or to minimise damage in accidents or chemical spills
 

Kaatie

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Neutralisation reactions should be used to minimise damage in accidents or chemical spills unless the spill in on the skin (or any other body part). This is because neutralisation is an exothermic reaction and if the acid is strong then a large amount of heat will be produced, burning the body, causing a great amount of harm.

Explain how a porous divider is similar to a salt bridge
 

x.Exhaust.x

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Neutralisation reactions should be used to minimise damage in accidents or chemical spills unless the spill in on the skin (or any other body part). This is because neutralisation is an exothermic reaction and if the acid is strong then a large amount of heat will be produced, burning the body, causing a great amount of harm.

Explain how a porous divider is similar to a salt bridge
You didn't assess the question (Make a judgement of value, quality, outcomes, results or size).
 

GUSSSSSSSSSSSSS

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You didn't assess the question (Make a judgement of value, quality, outcomes, results or size).
tbh reading thru the answers, not many ppl are answering the q's with full mark responses..

that one's just anotha example of it
 

kwabon

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tbh reading thru the answers, not many ppl are answering the q's with full mark responses..

that one's just anotha example of it
woah woah gus mate, take it easy, since no one is really saying how many marks the question is worth, u cant really say that. true that most of them are not assessing or evaluating, but since they get the gist of what the question is asking and how to answer it, they are fine, but if they did not assess or discussed the question, some of us, should just remind them that they should have assessed, and then move on with the next question.

about the next question "how is a porous divider similar to a salt bridge" lol, i have no clue.
 

GUSSSSSSSSSSSSS

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woah woah gus mate, take it easy, since no one is really saying how many marks the question is worth, u cant really say that. true that most of them are not assessing or evaluating, but since they get the gist of what the question is asking and how to answer it, they are fine, but if they did not assess or discussed the question, some of us, should just remind them that they should have assessed, and then move on with the next question.

about the next question "how is a porous divider similar to a salt bridge" lol, i have no clue.
hehehe i think a rage quit is in order then LOL!!
 

Kaatie

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how didnt i assess it?i said that it should be neutralised unless on the human body, that is a judgement based on safety and said the results of what would happen if you did
 

Pwnage101

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In your course you conducted a first-hand investigation to compare the reactivates, in bromine water, of an appropriate alkene and its corresponding alkane.

(a) Identify the dependent variable in your investigation (1 mark)

(b) Name and draw the structural formula for the alkene used in your investigation (1 mark)

(c) Justify the selection of this alkene. (2 marks)

Straight from Q 16 of the 2008 Catholic Trial (CSSA). Marks are as they appeared in the paper.
 

jediloc

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hey lets go again then...
i'll get it started again!!

ok

what is a commercial radioisotope?!?

how is it manufactured?!?!:jedi:
 

jet

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To continue with the line of incomplete answers,
A porous divider is similar to a salt bridge in that it plays the same function in a cell; to allow for the balancing of the charge distribution in the cell. It allows ions in the solution to pass between the half cells, allowing each half cell to maintain a neutral charge.

For the other one:
Dependent Variable: Colour of solution/Change in colour of solution

I will copy and paste the structural formula from my notes:

Cyclohexene

One factor which justifies the use of this alkene is the fact that it is a liquid at room temperature, making it much easier to contain, and work with in a fume cupboard. Also, cyclohexene is a clear liquid, which allows the colour change to be easily observed, adding to the reliability of the experiment.

Question:
How can biomass be used as an alternative source as opposed to fossil fuels for the petrochemical industry. (In our half yearly, this was an assess question work 8 marks)
 

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