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

Yaay! I think this paper went quite well

How many people put AB were similar and CD were different?
And how many people wrote magnesium sulfate and chloride for the last question?

Yeah same here but I found out on this thread that there was a question I didn't see (about the ion tests with A,B,C,D)! I just don't remember coming across the question which is kind of bugging me... but at least I answered all the other Qs

That question sucked...it could surely be interpreted both ways?

AB same because they both produce hydrogen gas and are acidic and CD different because they were different tests.

OR

CD same because they both produced white precipitate and it asked what he could see and AB different because one would be more reactive and fizz more or one would have a more acidic pH than the other yet he wouldn't see a different if the solution was simply white?

(I got so confused and changed my answer)

Exact same feelings - messed up stupid and simple questions though.

How many marks was the last question worth?

For the rates of reaction 6 marker, did anyone put that the rate of reaction was fast at first because of the high concentration and large surface area of the zinc metal and then it decreased at B because some of the reactants were used up and then it stopped at C because all the reactants had been used up in the collisions and there were no more reactions to be made by the collisions? or something along those lines

How many marks does everyone think ill get if i put this

C similar because it formed an insoluble precipitate
D similar because it formed an insoluble precipitate

A different because hydrochloric acid and sulfuric acid have different pH's
B different because adding magnesium would result in different salts being made (magnesium chloride and magnesium sulfate)


each section was worth 3 marks so 6 overall

I don't think that's right because of the c and d bit. I don't think they're looking for the same explanation. But you might be right if the mark scheme accepts any answer with a reasonable explantion.

Was is h2SO4 or H+H+SO4
And I thought reduction was adding electrons (thats what it said about electrolysis) not removing oxygen

I put the exact same as you, I think it's right, so 6 marks...haha


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I didnt understand because it only showed hcl with nitrate solution not with the barium and sulphuric acid was only shown reacting with the barium not the silver nitrate

Does no one know??

Don't get so happy because there's a totally different answer which makes just as much sense:

A similar as both HCL and H2SO4 are acids so their PH's are lower than 7.
B similar as they both react to produce hydrogen.

C different because it produces a white precipitate for the reaction with HCL whereas the H2SO4 would not react with silver.
D different because it produces a white precipitate when the H2SO4 reacts with barium whereas barium and HCL would not form precipitates.

Was is h2SO4 or H+H+SO4
And I thought reduction was adding electrons (thats what it said about electrolysis) not removing oxygen