Preliminary 2012 Chemistry Marathon (1 Viewer)

[Kimyia]

A solution would mean that it is dissolved in water. Therefore, to get rid of the water, evaporation to dryness should be first used. Then the NaCl crystals can be distilled, due to the differences in their boiling points.

Explain 4 reasons why there are more metals available for people to use now than there were 200 years ago (6 marks).

???
Isn't distillation used for liquids only - either straight liquids or gases that have been cooled to such temperatures at which they exist as liquids. Then their difference in boiling points is exploited to separate them.
In your answer, shouldn't you only use evaporation to dryness as it exploits the difference in boiling points of the liquid solvent and the melting/boiling point of the solute (the NaCl).

Edit: nm, it asked for effectiveness.

 

[planino]

A solution would mean that it is dissolved in water. Therefore, to get rid of the water, evaporation to dryness should be first used. Then the NaCl crystals can be distilled, due to the differences in their boiling points.

0/2 marks, distillation is the more appropriate process. Water can be boiled off at 100 degrees, crystallising out the NaCl and water can be collected as the distillate. Evaporation is not a suitable process as water would have been lost as steam.

 

[theind1996]

0/2 marks, distillation is the more appropriate process. Water can be boiled off at 100 degrees, crystallising out the NaCl and water can be collected as the distillate. Evaporation is not a suitable process as water would have been lost as steam.

OH YEA WTH. BTW, I THOUGHT planino meant separating the Na from the Cl as well. I misunderstood the question. And "appropriate" is a bit of an ambiguous term.

 

[Kimyia]

0/2 marks, distillation is the more appropriate process. Water can be boiled off at 100 degrees, crystallising out the NaCl and water can be collected as the distillate. Evaporation is not a suitable process as water would have been lost as steam.

Yeah I get it.

 

[planino]

OH YEA WTH. BTW, I THOUGHT planino meant separating the Na from the Cl as well. I misunderstood the question. And "appropriate" is a bit of an ambiguous term.

Ah yeah, should have said 'suitable' or something like that

 

[theind1996]

Ah yeah, should have said 'suitable' or something like that

Na, you should have clearly stated: in order to achieve water in liquid form.

BTW, answer my question from before:

Explain 4 reasons why there are more metals available for people to use now than there were 200 years ago (6 marks).

 

[superSAIyan2]

1) Before they did not have the facilities (e.g. blast furnaces or electrolysis) which could provide the extensive energy requiored to reduced a metal from ore to element. They only had weak furnaces
2) Large scale production and distribution of electricity allowed very reactive metals, such as Al which doesnt have the tendency to be reduced, to be extracted.
3) Most metals are reactive and are found in compounds rather than in pure elemental form in nature
4) Increasing world demand, as a result of risingpopulation and urban development, has caused the increase in productivity

Question : Describe how you can confirm that copper carbonate has been thermally decomposed using a chemcial reaction. 3M

 

[crazy_paki123]

Preliminary Chemistry is REALLY EZY!!! if u cant get yr 11 chem, dream on about doing well in year 12 chem

 

[theind1996]

Preliminary Chemistry is REALLY EZY!!! if u cant get yr 11 chem, dream on about doing well in year 12 chem

Alright then, thanks for that unnecessary, useless comment.

I can see that you haven't grasped Year 4 English.

 

[bleakarcher]

alright theind1996, next question?

 

[bleakarcher]

1) Before they did not have the facilities (e.g. blast furnaces or electrolysis) which could provide the extensive energy requiored to reduced a metal from ore to element. They only had weak furnaces
2) Large scale production and distribution of electricity allowed very reactive metals, such as Al which doesnt have the tendency to be reduced, to be extracted.
3) Most metals are reactive and are found in compounds rather than in pure elemental form in nature
4) Increasing world demand, as a result of risingpopulation and urban development, has caused the increase in productivity

Question : Describe how you can confirm that copper carbonate has been thermally decomposed using a chemcial reaction. 3M

cant you just take the temperature of the surroundings before and after the reaction?

 

[Jacob888]

CuCO3 -> CuO + CO2
1- Test the CO2 gas in limewater, the limewater should go milky in the presence of CO2
2- Add H2O to the CuO solution. This should form CuOH which is a basic substance. This can be tested with universal indicator which should turn a bluish purple colour in basic substances.

1) Before they did not have the facilities (e.g. blast furnaces or electrolysis) which could provide the extensive energy requiored to reduced a metal from ore to element. They only had weak furnaces
2) Large scale production and distribution of electricity allowed very reactive metals, such as Al which doesnt have the tendency to be reduced, to be extracted.
3) Most metals are reactive and are found in compounds rather than in pure elemental form in nature
4) Increasing world demand, as a result of risingpopulation and urban development, has caused the increase in productivity

Question : Describe how you can confirm that copper carbonate has been thermally decomposed using a chemcial reaction. 3M

 

[Kimyia]

cant you just take the temperature of the surroundings before and after the reaction?

You need to show that it has actually decomposed.

 

[bleakarcher]

oh right, I didn't answer it completely lol.

 

[planino]

1) Before they did not have the facilities (e.g. blast furnaces or electrolysis) which could provide the extensive energy requiored to reduced a metal from ore to element. They only had weak furnaces
2) Large scale production and distribution of electricity allowed very reactive metals, such as Al which doesnt have the tendency to be reduced, to be extracted.
3) Most metals are reactive and are found in compounds rather than in pure elemental form in nature
4) Increasing world demand, as a result of risingpopulation and urban development, has caused the increase in productivity

o.o step back... xD

 

[planino]

CuCO3 -> CuO + CO2
1- Test the CO2 gas in limewater, the limewater should go milky in the presence of CO2
2- Add H2O to the CuO solution. This should form CuOH which is a basic substance. This can be tested with universal indicator which should turn a bluish purple colour in basic substances.

Next question please

 

[Jacob888]

QUESTION: Name a mixture from either the biosphere, lithosphere, hydrosphere or atmosphere and then briefly describe the industrial seperation process used to seperate it. Also name a use for the final products. (4 Marks)

 

[superSAIyan2]

Biosphere - Blood, separate using centrifuge which separates based on differences in density and obtained components can be used in forensic science and medicinal/pharmaceutical industries
Hydrosphere - Salt water, use evaporation to separate salt from water due to differences in BP, obtain salt which is used for consumption?
Lithosphere - Crude oil , use fractional distillation to separate components based on their volatility and kerosene can be obtained for jet fuel
Atmosphere - Air itself is a mixture, separate gases using fractional distillation and i think zeolite sieves, results can indicate the percent composition of air in a region and indicates pollution levels

Question : Define Avogrado's Law.

 

[superSAIyan2]

Oh damn i didnt see that Jacob888's question said either. I thought it said from the biosphere, lithosphere.....

 

[superSAIyan2]

o.o step back... xD

Is planino a weird anagram of yours for piano lady