GCSE OCR 21st Century Triple Science (CBP1-7) Thread Watch

monisj1
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#981
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(Original post by mmaryam)
For C5, weren't we only meant to discuss the data from 2010?

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I only discussed data from 2010? Is that correct
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lyricalvibe
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#982
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(Original post by lucysnell)
For the testing ions I put that C and B were alike because for C they both produced an insoluble solid compound in the form of a white precipitate. I put B because when reacting with magnesium ribbon they would both produce a salt and hydrogen.

D would only work for the sulfuric acid as there would be no change/precipitate with hydrochloric acid. I put that A would be dissimilar as the pH of one acid compound would differ to the pH of another acidic compound.

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I put the same except I got a bit confused and thought D and sulphuric acid must do something so I said a displacement reaction would occur of which I know is wrong but I was so set on it can't be nothing -_- apart from that though I literally said the same thing

what did you get for the two boxes asking for ions formed on 3rd from last page?
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student97
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#983
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in the final salts question i put sodium chloride (NaCl)
and sodium sulfate (NaSO4) But i should've put a 2 after the Na
so stressed about that ugh
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lyricalvibe
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#984
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(Original post by mmaryam)
For C5, weren't we only meant to discuss the data from 2010?

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It was asking for why scientist are concerned and said use information about copper so you could talk about any of the data I think
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lucysnell
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#985
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I put H+ and Cl- for hydrochloric acid and H+, H+, SO4 2- for sulfuric acid xxx

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ToLiveInADream
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#986
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In general, nice but not as great as unit 1. I know I got the last question wrong because I put water for both, like an idiot haha.
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User1452521
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#987
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(Original post by monisj1)
I only discussed data from 2010? Is that correct
Yes but to get into level 3 marking you had to discuss the past (1990-2010) and the future (2010-2040). I also did some calculations to find out how long the world would have copper for till it runs out and then if we recycled copper how long it would last. I got 120 years without recycling and then 180 years recycling- these are estimations.


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olmyster911
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#988
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(Original post by Sulfur)
A shows a slow reaction
B shows a greater rate of reaction
C shows the rate of reaction has ended/stationary
At A, the change in mass is little because little collisions occur, so the rate of reaction is slower so less hydrogen gas is given off - small change on balance
At B, the change in mass is greater because more collisions occur, so the rate of reaction is faster and more hydrogen gas is given off - greater change on balance
At C, no change in mass, no collisions, no rate of reaction - dissolved
At B, the rate is greater because after A the zinc will have been broken down from a solid into more chunks so there's a greater surface area which speeds up the rate of reaction because the HCl atoms can react on the surface.
I thought that A was the fastest part of the reaction because on the graph it was a steep decrease in mass?? At B it steadied out until it stopped completely at C




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mmaryam
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#989
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#989
(Original post by olmyster911)
I thought that A was the fastest part of the reaction because on the graph it was a steep decrease in mass?? At B it steadied out until it stopped completely at C

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Yes, you're right. A was the steepest so it had the fastest rate of reaction.



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ToLiveInADream
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(Original post by Sulfur)
C4:

Lithium has two shells, Sodium has three shells and Potassium has four shells (2,1) (2,8,1) (2,8,8,1)
Increase the number of electrons increases the radius of the atom and the energy need decreases
Supported by using all of the data into the previous point
Atom radius increases because there are more protons and neutrons in the nucleus and the number of shells increases because there are more electrons
Explained why the conclusion was correct: Less energy is needed because the atom is bigger so the electrostatic attraction between the nucleus and electrons is weaker as the atom increases in size

C5:

1900-1960 was quite a small increase from 1 million to 5 (gradually increased)
1960-2010 began to increase much more from 5 million to 20 million
2010-2030 predicted to increase exponentially from 20 million to 30 million which is a 50% rise
Positive correlation between years progressed and demand
Scientists worry because copper isn't sustainable, needed for transporting energy/work tools for example
Demand increases as the supply becomes limited so it'll eventually run out
Graph only shows four countries and the demand for these is more more than the supply


C6:

A shows a slow reaction
B shows a greater rate of reaction
C shows the rate of reaction has ended/stationary
At A, the change in mass is little because little collisions occur, so the rate of reaction is slower so less hydrogen gas is given off - small change on balance
At B, the change in mass is greater because more collisions occur, so the rate of reaction is faster and more hydrogen gas is given off - greater change on balance
At C, no change in mass, no collisions, no rate of reaction - dissolved
At B, the rate is greater because after A the zinc will have been broken down from a solid into more chunks so there's a greater surface area which speeds up the rate of reaction because the HCl atoms can react on the surface.
A had a steep decrease in a short amount of time which means it was turning into a gas very quickly! This means it has a greater rate of reaction..?
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User1452521
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#991
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(Original post by lucysnell)
I put H+ and Cl- for hydrochloric acid and H+, H+, SO4 2- for sulfuric acid xxx

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I did the same but added OHminus to both because they created H2O as a product also and also because they were both dilute acids- not sure f I'm right though


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lucysnell
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#992
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#992
I thought it only asked for ions? Hm doubting my answers now xx

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Sulfur
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#993
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#993
(Original post by olmyster911)
I thought that A was the fastest part of the reaction because on the graph it was a steep decrease in mass?? At B it steadied out until it stopped completely at C

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(Original post by ToLiveInADream)
A had a steep decrease in a short amount of time which means it was turning into a gas very quickly! This means it has a greater rate of reaction..?
Ah sugar.
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olmyster911
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#994
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(Original post by brodingoson)
I did the same but added OHminus to both because they created H2O as a product also and also because they were both dilute acids- not sure f I'm right though


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I don't think they were asking for the product e.g. H2O


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olmyster911
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#995
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(Original post by Sulfur)
Ah sugar.
Did you put that the rate of reaction was slow at point A?


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User1452521
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#996
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(Original post by lucysnell)
I thought it only asked for ions? Hm doubting my answers now xx

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Yes it did, I'm not really 100% certain, this is just what I and my friends got. Water isn't an ion but a product that's why i added it. I have no idea ! :L


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ToLiveInADream
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#997
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Oh ans btw about the copper ion question, the + one was the copper ION but the - was the electrons (metallic bonding).
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Preshh
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#998
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Absolutely hated that exam! I revised so much and most things didn't come up. Only 6 marker I liked was the C4 one. C5 I blabbed and C6 I don't even know. For c4, how could they make 8 marks on Dobereiner? What about ionic bonding, the halogens etc -_-. And the stuff about ph metre and magnesium ribbon in c6, I guessed CD similar cause of a white precipitate and AB different. For C5 i liked the electrolysis question. Overall though it was terrible. Was hoping for an a* but not sure about that now
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ToLiveInADream
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#999
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(Original post by Sulfur)
Ah sugar.
No worries, your science is still spot on! You're still likely to get around 5.
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Sulfur
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#1000
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#1000
(Original post by olmyster911)
I thought that A was the fastest part of the reaction because on the graph it was a steep decrease in mass?? At B it steadied out until it stopped completely at C

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Yup I guess. Damn I thought since it was a solid and then broke up the surface area would've increased and faster reaction etc... Whoops!
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