19th May 2016 - OCR 21st Century Science C1 C2 C3 Exam

So happy I revised risks of plasticizers last min... that was something I had completely forgotten was in the spec! Anyone else face any questions they were not expecting??

There were enough boxes, some of the options were incorrect - clay is insoluble, for example.

guyssssssss the test was good! Can everyone start to remember the questions so we can possibly make an unofficial mark scheme?
1a) Why does ethene burn in oxygen and not air? (or something like that)
1b) What compound is ethene
1c) Drawing molecules

guyssssssss the test was good! Can everyone start to remember the questions so we can possibly make an unofficial mark scheme?
1a) Why does ethene burn in oxygen and not air? (or something like that)
1b) What compound is ethene
1c) Drawing molecules

Ethyne, not ethene.

sorry grammar police

Not a case of grammar police - one is an alkyne with formula C2H2, and one is an alkene with formula C2H4! They are completely different compounds...

Get your facts right before you attempt to insult someone else

i put to fully combust the air contains other compounds and may result in incomplete combustion

Hey guys!

I dunno if this might b helpful but I tried to remember all the questions and this is what I came up with (I'm not sure of the answers tho so pls don't kill me);

1) (1 mark) "Oxygen allows the hydrocarbons to reach higher temperatures, therefore they burn more rapidly"

2) (1 mark) Hydrocarbons

3) (2 marks) In the first box you had to draw three black circles with two small white circles on top of each one. In the second box I think you only had to draw a circle with a patern of lines and two small white circles on top of it.

3) (2 marks) Tick boxes. Now, here I now for sure that one of them was at the bottom and it said said something along the lines of not complete combustion, I think. The other one was either " all carbon atoms react with oxygen" or "some carbon atoms react with oxygen" I reckon it was the second one.

4) (2 marks) "Catalytic converters convert carbon monoxide into carbon dioxide" (oxidation reaction). "Catalytic converters convert nitrogen monoxide into nitrogen and oxygen" (reduction recation)

5) (6 marks) You had to talk about the advantages and disadvantages of Car A (which used petrol) and Car B (which used diesel). Some of the points I personally made were that Car B was much more efficient as the amounts of carbon monoxide and carbon particulates were very small. I then talked about the effects that these pollutants could have had in the environment if they were found in large amounts. For disadvantages I wrote that it produced more nitrogen monoxide, which could then react with more oxygen in the air to poduce nitrogen dioxide, which then reacted with the moisture in clouds to produce acid rain.

6) (1 mark) You basically had to guess the amounts of CO2 produced in 2020 (or something like that). I put 10500. A lot of people in my school wrote 10400 so I guess the range the examiner will take into account may vary from 10300 to 10800.

7) (2 marks) You had to talk about why it was difficult to tell how the amounts of fossil fuels may vary within the pass of the years. I mentioned how they were a limited resource, therefore we would eventually run out of them and I also said how humans may use other sources of energy in the future instead of fossil fuels.

8) (2 marks) You had to compare the previous graph with a new one. I just said something along the lines of how "as more fossil fuels are burnt, the higher the temperatures on Earth". I truly do not remember what I wrote for this question.

9) (1 mark) You had to spot the outlier which was 13 in test number 3.

10) (1 mark) You had to talk about how the pupils had to (or not) consider the outlier. I said they could repeat the measurements in order to increase confidence, or they could check if the outlier was caused by a human error and then decide if they should consider it or not. I am really unsure aout this question so if it is wrong pls tell meh

11) (2 marks) Calculate the mean including the outlier which was 21

12) (2 marks) You had to talk about how rulers were different from each other using the data provided.

13) (6 marks) Matt was right. You then had to apply ideas about science and how the other two were wrong because it could affect the final outcome of results.

14) (1 mark) Draw a monomer molecule; which consisted of two black circles joined together with two smaller white circles on top and bottom for the first black circle, and one white small circle on top of the second one with a large circle on bottom with stripes on the surface (sorry if this sounds confusing I really don't know how to explain it properly :s)

15) (3 marks) Talk about how plasticisers could affect the properties of a polymer. They make it more flexible as they decrease the forces between them.

16) (4 marks) Talk about crude oil and the different properties it has. Also you had tomention how different chains produced different properties and boiling points.

17) (6 marks) Eco-friendly trainers. The company was right and you just had to use data from the table and give reasons for your opinion as well as adding LCA points to back them up. They required more information on manufacture, transport, etc.

18) (3 marks) B A G F. First the water is pumped through a pipe. It is then mixed with salt, It is then extracted because of pressure and evaporated to form salt crystals.

19) (1 mark) Salt is used to preserve/conserve food so it lasts longer

20) (2 marks) Explain how PVC can be harmful in order to wrap foods. I really messed up this question so I do not know the definite answer if u guys remember pls tell meh, again .

21) (1 mark) PVC products contain hydrogen,carbon and chlorine

22) (2 marks) Electrolysis producs include sodium hydroxide, hydrogen and chlorine.

23) (2 marks) You had to complete the table with a set of two missing results. Again I ***** up this question so don't even bother asking me for the answer.

24) (4 marks) You had to use the table and explain how something has evolved. I don't even remember this question so

Hope it's helpful and good luck with Physics on Wedsday

Hey guys!

I dunno if this might b helpful but I tried to remember all the questions and this is what I came up with (I'm not sure of the answers tho so pls don't kill me);

1) (1 mark) "Oxygen allows the hydrocarbons to reach higher temperatures, therefore they burn more rapidly"

2) (1 mark) Hydrocarbons

3) (2 marks) In the first box you had to draw three black circles with two small white circles on top of each one. In the second box I think you only had to draw a circle with a patern of lines and two small white circles on top of it.

3) (2 marks) Tick boxes. Now, here I now for sure that one of them was at the bottom and it said said something along the lines of not complete combustion, I think. The other one was either " all carbon atoms react with oxygen" or "some carbon atoms react with oxygen" I reckon it was the second one.

4) (2 marks) "Catalytic converters convert carbon monoxide into carbon dioxide" (oxidation reaction). "Catalytic converters convert nitrogen monoxide into nitrogen and oxygen" (reduction recation)

5) (6 marks) You had to talk about the advantages and disadvantages of Car A (which used petrol) and Car B (which used diesel). Some of the points I personally made were that Car B was much more efficient as the amounts of carbon monoxide and carbon particulates were very small. I then talked about the effects that these pollutants could have had in the environment if they were found in large amounts. For disadvantages I wrote that it produced more nitrogen monoxide, which could then react with more oxygen in the air to poduce nitrogen dioxide, which then reacted with the moisture in clouds to produce acid rain.

6) (1 mark) You basically had to guess the amounts of CO2 produced in 2020 (or something like that). I put 10500. A lot of people in my school wrote 10400 so I guess the range the examiner will take into account may vary from 10300 to 10800.

7) (2 marks) You had to talk about why it was difficult to tell how the amounts of fossil fuels may vary within the pass of the years. I mentioned how they were a limited resource, therefore we would eventually run out of them and I also said how humans may use other sources of energy in the future instead of fossil fuels.

8) (2 marks) You had to compare the previous graph with a new one. I just said something along the lines of how "as more fossil fuels are burnt, the higher the temperatures on Earth". I truly do not remember what I wrote for this question.

9) (1 mark) You had to spot the outlier which was 13 in test number 3.

10) (1 mark) You had to talk about how the pupils had to (or not) consider the outlier. I said they could repeat the measurements in order to increase confidence, or they could check if the outlier was caused by a human error and then decide if they should consider it or not. I am really unsure aout this question so if it is wrong pls tell meh

11) (2 marks) Calculate the mean including the outlier which was 21

12) (2 marks) You had to talk about how rulers were different from each other using the data provided.

13) (6 marks) Matt was right. You then had to apply ideas about science and how the other two were wrong because it could affect the final outcome of results.

14) (1 mark) Draw a monomer molecule; which consisted of two black circles joined together with two smaller white circles on top and bottom for the first black circle, and one white small circle on top of the second one with a large circle on bottom with stripes on the surface (sorry if this sounds confusing I really don't know how to explain it properly :s)

15) (3 marks) Talk about how plasticisers could affect the properties of a polymer. They make it more flexible as they decrease the forces between them.

16) (4 marks) Talk about crude oil and the different properties it has. Also you had tomention how different chains produced different properties and boiling points.

17) (6 marks) Eco-friendly trainers. The company was right and you just had to use data from the table and give reasons for your opinion as well as adding LCA points to back them up. They required more information on manufacture, transport, etc.

18) (3 marks) B A G F. First the water is pumped through a pipe. It is then mixed with salt, It is then extracted because of pressure and evaporated to form salt crystals.

19) (1 mark) Salt is used to preserve/conserve food so it lasts longer

20) (2 marks) Explain how PVC can be harmful in order to wrap foods. I really messed up this question so I do not know the definite answer if u guys remember pls tell meh, again .

21) (1 mark) PVC products contain hydrogen,carbon and chlorine

22) (2 marks) Electrolysis producs include sodium hydroxide, hydrogen and chlorine.

23) (2 marks) You had to complete the table with a set of two missing results. Again I ***** up this question so don't even bother asking me for the answer.

24) (4 marks) You had to use the table and explain how something has evolved. I don't even remember this question so

Hope it's helpful and good luck with Physics on Wedsday

thanku so much even though i failed

I think you pretty much nailed the answers, you also have very good memory!

The only ones that I'd elaborate on are:

15) Why plasticisers make PVC soft and flexible. [3 marks]
Sit between the chains of PVC and forces them apart, making the forces weaker.

16) Talking about why diesel and fuel have different boiling points. [4 marks]
Fuel oil has a longer chain length than diesel (1) This means that it has more intermolecular forces (2) As a result more energy is required to break the intermolecular forces so it can move freely as a gas. (3) This means diesel has a higher boiling point. (4)
ORA.

20) Why it's harmful to wrap PVC with a plasticiser in food. [Also, I think this was 3 marks]
Plasticiser can leach out of the PVC into food sources. (1) They are toxic (2) and can accumulate in humans. (3)
If you wrote anything to that effect then you'll probably get the marks.

23) Fill in the table with standard form. [2 marks]
Apparently the answers were 1.6 * 10^6 and 10,000 however that hasn't been confirmed.
(I wrote 2 * 10^6 and 10,000 and I guessed both of those answers so hopefully I get one mark. Furthermore, don't be disheartened if you didn't get either of those answers because despite how oddly difficult it was a pose to the rest of the test, it is only worth 2 marks. Frankly, I'm not too fussed if I got it right or wrong.)

24) Use the table to describe why the chlorine levels have changed over the past 50 years.
I wasn't too confident on this question but I'm guessing you need to talk about:
Chlorine levels increasing because there is more demand for it (chlorination)
Less electricity is being required for electrolysis because we're finding more efficient ways to undergo electrolysis.
Chlorine is being created from waste products (e.g. hydrogen chlorine can be oxidised to hydrogen and chlorine)
Any argument that makes sense is probably accepted.

What do you guys think will be for an A*?