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OCR Salters B - Chemistry of Natural Resources June 2010 (post discussion)
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aj.x
heya guys, just a few questions...
as there isn't many new spec papers, i've been doing old ones, and i was just wondering if we need to know about the following:
1. froth flotation
2. vacuum filteration
and also, in the pre-lease, figure 2... is that homolytic fission, because i produces radicals?!
help please...thank you! x
as there isn't many new spec papers, i've been doing old ones, and i was just wondering if we need to know about the following:
1. froth flotation
2. vacuum filteration
and also, in the pre-lease, figure 2... is that homolytic fission, because i produces radicals?!
help please...thank you! x
We do not have to know those 2 things you have listed
and yes UV is always Homolytic
hahahah
hi, does anyone know all the different regeants and conditions we need to know?! i have never been taught theese, and they are everywhere in previous exam papers! does anyone have a list or something? please help!
erm...i'm pretty sure these are corect.
- Alkenes to alkanes: add hydrogen and heat with a platinum catalyst at room temperatuure
- adding bromine to an alkene- goes orange to colourless, this is electrophillic addition.
- alkenes to alcohols: heat with high temp and pressure with concentrated sulphuric acid and then hydrolyse with water.
- alcohols to alkenes- this is elimation. reflux with concentrated sulphuric acid at 170 degrees. concentrated sulphuric acid is a dehydrating agent. it is elimination because h2o is formed.
-Oxidising alocohols.
1. primary alcohols oxidise to aldehydes, and if they are heated more they become carboxylic acids.
primary>aldehydes: heat/distill with acidified potassium dichromate.
aldehydes> carboxylic acid: heat under reflux with adicified potassium dichromate.
2. secondary alcohols oxides to be come ketones: heat with acidified potassium dichromate
3. tertiary alchols do not oxidise.
i think thats all the main ones, and i'm really sorry if they are not correct! ...hope that helps! x x x
aj.x
erm...i'm pretty sure these are corect.
- Alkenes to alkanes: add hydrogen and heat with a platinum catalyst at room temperatuure
- adding bromine to an alkene- goes orange to colourless, this is electrophillic addition.
- alkenes to alcohols: heat with high temp and pressure with concentrated sulphuric acid and then hydrolyse with water.
- alcohols to alkenes- this is elimation. reflux with concentrated sulphuric acid at 170 degrees. concentrated sulphuric acid is a dehydrating agent. it is elimination because h2o is formed.
-Oxidising alocohols.
1. primary alcohols oxidise to aldehydes, and if they are heated more they become carboxylic acids.
primary>aldehydes: heat/distill with acidified potassium dichromate.
aldehydes> carboxylic acid: heat under reflux with adicified potassium dichromate.
2. secondary alcohols oxides to be come ketones: heat with acidified potassium dichromate
3. tertiary alchols do not oxidise.
i think thats all the main ones, and i'm really sorry if they are not correct! ...hope that helps! x x x
- Alkenes to alkanes: add hydrogen and heat with a platinum catalyst at room temperatuure
- adding bromine to an alkene- goes orange to colourless, this is electrophillic addition.
- alkenes to alcohols: heat with high temp and pressure with concentrated sulphuric acid and then hydrolyse with water.
- alcohols to alkenes- this is elimation. reflux with concentrated sulphuric acid at 170 degrees. concentrated sulphuric acid is a dehydrating agent. it is elimination because h2o is formed.
-Oxidising alocohols.
1. primary alcohols oxidise to aldehydes, and if they are heated more they become carboxylic acids.
primary>aldehydes: heat/distill with acidified potassium dichromate.
aldehydes> carboxylic acid: heat under reflux with adicified potassium dichromate.
2. secondary alcohols oxides to be come ketones: heat with acidified potassium dichromate
3. tertiary alchols do not oxidise.
i think thats all the main ones, and i'm really sorry if they are not correct! ...hope that helps! x x x
thankyou so much for these!!
can anybody verify and make sure they are correct because i have no clue!
Saphire1
Really sorry about the delay, I thought I'd posted them ... here are the answers I've got in my notes...sorry if they don't make any sense
1.Venus density compared to earth-
1= 100/100 82/95=0.86 (so less density)
2.Convert 700K into degrees Celsius-
700k -273=427celsius
3. A) Type of bond fission in figure 2-
Homolytic or photolysis
B) Write an equation for the reaction represented in fig 2-
H2O O +2H
C) It doesn’t contain a high enough frequency- not enough energy to break bonds
D) What type of particles are O and H?
Radicals
E) Is figure 2 initiation, propagation or termination?
Initiation as molecules at start and radicals at end
F) Write the equation for the reaction that occurs when H react together. Classify the type of reaction step.
H + H H2 termination
G) Why does ultraviolet dissociation of water not occur on Earth?
Ozone absorbs high energy UV stopping it from dissociating it and (? water on earth is mainly liquid?)
H) Calculate the frequency of the radiation needed to break the OH bond given that the bond enthalpy is 464kJ mol-1; the Avagadros constant is 6.02 times 10 23 and plank constant is 6.63 times 10 -34 Js ?
464/6.02 times 10 23 =7.71 times 10 -22 7.71 times 10 -22/6.63 times 10 -34 =1.16 times 10 12 J/mol-1
1.16 times 10 12 J/mol-1 times 1000 = 1.16 times 10 15 Hertz
4. A hydrogen isotope can be represented as 11H how can deuterium be represented? 21H
5. Summarise the evidence that has lead to scientists believing that the UV dissociation of water is the reason why Venus has no water?
Venus had more water than earth as it had the isotope deuterium which was heavier and less likely to escape. This was a ratio of 1000:1 of ordinary hydrogen to deuterium. The proportion of deuterium is about 10 times higher 100:1. The ratio was supposed to be originally the same so something caused the light hydrogen isotopes to disappear- must have evaporated. This could be the UV dissociation of water.
6. Explain why Venus started off warmer than the earth and has become hotter?
Closer to the sun. Water vapour started greenhouse heating. Co2 was baked out of the rocks further aggravating the greenhouse effect. A runaway greenhouse started. All the CO2 in the atmosphere and water dissociated away. Now CO2 maintains the extremely hot temperature.
7. Explain why Mars started off cooler than the earth and why it has become even cooler?
Too far from sun. The runaway refrigerator process took place which meant the water vapour in the atmosphere turned to liquid due to the cool temperature, this meant that CO2 combines with rock causing temperature to drop causing frozen water and most of the CO2 to be in the soil.
8. Explain why the temperature of the earth is just right?
Not too close or too far from the sun. Earth has life and liquid water keeping temperatures balanced and most of its CO2 in the rocks. Earth is a balance between hot extreme weather of Venus and cold extreme weather of Mars. It also has a steady green house affect due to life and so is just right.
9. Give an equation for a reaction that could occur when CO2 is baked out of rocks?
MgCO3 MgO + CO2
1.Venus density compared to earth-
1= 100/100 82/95=0.86 (so less density)
2.Convert 700K into degrees Celsius-
700k -273=427celsius
3. A) Type of bond fission in figure 2-
Homolytic or photolysis
B) Write an equation for the reaction represented in fig 2-
H2O O +2H
C) It doesn’t contain a high enough frequency- not enough energy to break bonds
D) What type of particles are O and H?
Radicals
E) Is figure 2 initiation, propagation or termination?
Initiation as molecules at start and radicals at end
F) Write the equation for the reaction that occurs when H react together. Classify the type of reaction step.
H + H H2 termination
G) Why does ultraviolet dissociation of water not occur on Earth?
Ozone absorbs high energy UV stopping it from dissociating it and (? water on earth is mainly liquid?)
H) Calculate the frequency of the radiation needed to break the OH bond given that the bond enthalpy is 464kJ mol-1; the Avagadros constant is 6.02 times 10 23 and plank constant is 6.63 times 10 -34 Js ?
464/6.02 times 10 23 =7.71 times 10 -22 7.71 times 10 -22/6.63 times 10 -34 =1.16 times 10 12 J/mol-1
1.16 times 10 12 J/mol-1 times 1000 = 1.16 times 10 15 Hertz
4. A hydrogen isotope can be represented as 11H how can deuterium be represented? 21H
5. Summarise the evidence that has lead to scientists believing that the UV dissociation of water is the reason why Venus has no water?
Venus had more water than earth as it had the isotope deuterium which was heavier and less likely to escape. This was a ratio of 1000:1 of ordinary hydrogen to deuterium. The proportion of deuterium is about 10 times higher 100:1. The ratio was supposed to be originally the same so something caused the light hydrogen isotopes to disappear- must have evaporated. This could be the UV dissociation of water.
6. Explain why Venus started off warmer than the earth and has become hotter?
Closer to the sun. Water vapour started greenhouse heating. Co2 was baked out of the rocks further aggravating the greenhouse effect. A runaway greenhouse started. All the CO2 in the atmosphere and water dissociated away. Now CO2 maintains the extremely hot temperature.
7. Explain why Mars started off cooler than the earth and why it has become even cooler?
Too far from sun. The runaway refrigerator process took place which meant the water vapour in the atmosphere turned to liquid due to the cool temperature, this meant that CO2 combines with rock causing temperature to drop causing frozen water and most of the CO2 to be in the soil.
8. Explain why the temperature of the earth is just right?
Not too close or too far from the sun. Earth has life and liquid water keeping temperatures balanced and most of its CO2 in the rocks. Earth is a balance between hot extreme weather of Venus and cold extreme weather of Mars. It also has a steady green house affect due to life and so is just right.
9. Give an equation for a reaction that could occur when CO2 is baked out of rocks?
MgCO3 MgO + CO2
Thanks alot by the wayy !!
Right just a few questions I have to discuss with anyone
...- First of all why does Earth having life keep CO2 balanced?
- Secondly, didn't both Earth and Mars start with water as liquid, but Earth had life and hence I good balance between co2 levels, wheras Mars it stayed liquid and so Mars cooled etc, but what caused the Earth to have life and Mars to not, if u get what i mean, i'm kinda confused
- Thirdly, moving on, my explanation to 5 was this, is this okay, what do u guys think:
There is evidence that alot of light H isotopes have escaped, both Earth and Venus were initially thought to have had a ratio of h/d 1000 to 1, but Venus is now 100 to 1. The heavier D isotope, is less likely to escape, and so the change in the ratio must be due to a loss of H isotopes. This loss of H istopes must be due to UV dissociation of water...
Any feedback on any on my queries above, greatly appeciated, cheers guys...
Saphire1
Questions on the Advanced Notice Article
1) Compare the density of Venus to that of the Earth.
2) Convert 700K into degrees Celcius.
3)
(a) What type of bond fission is shown in Fig 2?
(b) Write an equation for the reaction represented in Fig 2.
(c) Why will visible light not break the O-H bond?
(d) What type of particles are O and H?
(e) Classify the reaction step shown in Fig 2 as initiation, propagation or termination. Explain your answer.
(f) Write the equation for the reaction that occurs when H reacts together. Classify the type of reaction step.
(g) Why does ultraviolet dissociation of water not occur on Earth?
(h) Calculate the frequency of the radiation needed to break the O-H bond given that the bond enthalpy is 464 KJmol^-1; the Avogadro constant is 6.02 * 10^23 mol^-1 and the Plank Constant (h) is 6.63 * 10^-34 Js.
4) A hydrogen isotope can be represented as 1H. How can deuterium be represented?
5) Summarise the evidence that has led scientists to believe that the ultraviolet dissociation of water is the reason that there is no water on Venus.
6) Explain why Venus started off warmer than the Earth and has become even hotter.
7) Explain why Mars started off cooler than the Earth and why it has become even colder.
8) Why is the Earth's temperature "just right"?
9) Give an equation for a reaction that could occur when "CO2 is baked out of rocks".
1) Compare the density of Venus to that of the Earth.
2) Convert 700K into degrees Celcius.
3)
(a) What type of bond fission is shown in Fig 2?
(b) Write an equation for the reaction represented in Fig 2.
(c) Why will visible light not break the O-H bond?
(d) What type of particles are O and H?
(e) Classify the reaction step shown in Fig 2 as initiation, propagation or termination. Explain your answer.
(f) Write the equation for the reaction that occurs when H reacts together. Classify the type of reaction step.
(g) Why does ultraviolet dissociation of water not occur on Earth?
(h) Calculate the frequency of the radiation needed to break the O-H bond given that the bond enthalpy is 464 KJmol^-1; the Avogadro constant is 6.02 * 10^23 mol^-1 and the Plank Constant (h) is 6.63 * 10^-34 Js.
4) A hydrogen isotope can be represented as 1H. How can deuterium be represented?
5) Summarise the evidence that has led scientists to believe that the ultraviolet dissociation of water is the reason that there is no water on Venus.
6) Explain why Venus started off warmer than the Earth and has become even hotter.
7) Explain why Mars started off cooler than the Earth and why it has become even colder.
8) Why is the Earth's temperature "just right"?
9) Give an equation for a reaction that could occur when "CO2 is baked out of rocks".
Heyya, thanks so much!!!!
With the last question could you also say CaCO3 -> CaO + CO2???? I thought the 'rocks' might be limestone LOL? :P I guess there are a couple different equations.
rainbowsss
Thanks alot by the wayy !!
Right just a few questions I have to discuss with anyone...
- First of all why does Earth having life keep CO2 balanced?
Right just a few questions I have to discuss with anyone
...- First of all why does Earth having life keep CO2 balanced?
Because life udergoes respiration which gives out CO2 (keeps the Earth warm by aborbing IR radiation...bonds vibrate more vigorously...turned to kinetic energy...increases temperature), and then trees take in some of the CO2 for photosynthesis. Long term I suppose you could look at locked up CO2 i fossils.
Hope that helped
hahahah
does anyone have the june2009 paper with answers? if u do, can u put it onto here please!!
http://www.ocr.org.uk/download/pp_09_jun/ocr_41470_pp_09_jun_gce_f332_01.pdf
http://www.ocr.org.uk/download/ms_09/ocr_41000_ms_09_gce_jun.pdf
rainbowsss
Thanks alot by the wayy !!
Right just a few questions I have to discuss with anyone...
- Secondly, didn't both Earth and Mars start with water as liquid, but Earth had life and hence I good balance between co2 levels, wheras Mars it stayed liquid and so Mars cooled etc, but what caused the Earth to have life and Mars to not, if u get what i mean, i'm kinda confused
Right just a few questions I have to discuss with anyone
...- Secondly, didn't both Earth and Mars start with water as liquid, but Earth had life and hence I good balance between co2 levels, wheras Mars it stayed liquid and so Mars cooled etc, but what caused the Earth to have life and Mars to not, if u get what i mean, i'm kinda confused
If you look at the flowchart in the advanced notice article, all three start off with water vapour. Venus gets hotter which leads to ultraviolet dissociation of water vapour (which is why Venus is a very dry place) Mars get cooler so the water vapour the cools to liquid and so on. Earth is the right distance away from the su and so has the right temperature to support life, if you read the article it actually says that previously the temperatures on the two other planets may have been able to support life but now they are either too cold or too hot. Mars is so cold that any water is frozen.
Hope that helped- I'm revising this at the moment.
aj.x
erm...i'm pretty sure these are corect.
- Alkenes to alkanes: add hydrogen and heat with a platinum catalyst at room temperatuure
- adding bromine to an alkene- goes orange to colourless, this is electrophillic addition.
- alkenes to alcohols: heat with high temp and pressure with concentrated sulphuric acid and then hydrolyse with water.
- alcohols to alkenes- this is elimation. reflux with concentrated sulphuric acid at 170 degrees. concentrated sulphuric acid is a dehydrating agent. it is elimination because h2o is formed.
-Oxidising alocohols.
1. primary alcohols oxidise to aldehydes, and if they are heated more they become carboxylic acids.
primary>aldehydes: heat/distill with acidified potassium dichromate.
aldehydes> carboxylic acid: heat under reflux with adicified potassium dichromate.
2. secondary alcohols oxides to be come ketones: heat with acidified potassium dichromate
3. tertiary alchols do not oxidise.
i think thats all the main ones, and i'm really sorry if they are not correct! ...hope that helps! x x x
- Alkenes to alkanes: add hydrogen and heat with a platinum catalyst at room temperatuure
- adding bromine to an alkene- goes orange to colourless, this is electrophillic addition.
- alkenes to alcohols: heat with high temp and pressure with concentrated sulphuric acid and then hydrolyse with water.
- alcohols to alkenes- this is elimation. reflux with concentrated sulphuric acid at 170 degrees. concentrated sulphuric acid is a dehydrating agent. it is elimination because h2o is formed.
-Oxidising alocohols.
1. primary alcohols oxidise to aldehydes, and if they are heated more they become carboxylic acids.
primary>aldehydes: heat/distill with acidified potassium dichromate.
aldehydes> carboxylic acid: heat under reflux with adicified potassium dichromate.
2. secondary alcohols oxides to be come ketones: heat with acidified potassium dichromate
3. tertiary alchols do not oxidise.
i think thats all the main ones, and i'm really sorry if they are not correct! ...hope that helps! x x x
Fantastic thank you very much!
this thread is bloody amazing!!! After reading and make notes from this thread i'm not as stressed! Thanks everyone
Another thing our teacher kept telling us until we could say it backwards:
Venus
1) Water vapour contributes to the greenhouse effect (absorbs infra red radiation)
2) When absorbed, the bonds vibrate more vigorously, this is turned into kinetic energy which is passed on to other molecules by collisions.
3) This increases the temperature.
As it gets warmer = more water vapour is created = bonds vibrate more vigorously = more kinetic energy and so on...cycle!
Eventually it gets so hot that the CO2 is baked out of the rocks and because it itself is a greenhouse gas, it means that the planet gets even more hotter. The water vapour has undergone homolytic fission (absorbing high energy UV radiation) and become O and 2H. The 2H undergo a termination reaction to produce hydrogen gas which escapes into space.
Wow, typing this up makes it easier to remember.
Venus
1) Water vapour contributes to the greenhouse effect (absorbs infra red radiation)
2) When absorbed, the bonds vibrate more vigorously, this is turned into kinetic energy which is passed on to other molecules by collisions.
3) This increases the temperature.
As it gets warmer = more water vapour is created = bonds vibrate more vigorously = more kinetic energy and so on...cycle!
Eventually it gets so hot that the CO2 is baked out of the rocks and because it itself is a greenhouse gas, it means that the planet gets even more hotter. The water vapour has undergone homolytic fission (absorbing high energy UV radiation) and become O and 2H. The 2H undergo a termination reaction to produce hydrogen gas which escapes into space.
Wow, typing this up makes it easier to remember.
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