GCSE 21st Century Chemistry C1 C2 C3

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Reply 320

Kavinthan

Original post by Z-Dust

Hated this test. For the 2nd 6 marker I chose Polyester :frown:

i chose nylon and polyester.

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it had equal tensile strength

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similar stiffness/flexibility

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nylon was lighter but had a much higher water absorbency so when both is wet they'd be around the same weight

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they both sink in water too

Reply 321

aimeelovescats

I don't understand how it could be any that sink. It said it had to be light even when wet. If they sink then they must be heavy when wet. So it was the one that floats.

Reply 322

Kavinthan

Original post by aimeelovescats

I don't understand how it could be any that sink. It said it had to be light even when wet. If they sink then they must be heavy when wet. So it was the one that floats.

you're thick. why'd you do the higer paper if you are gonna give such b-tec answers

Reply 323

FlakeFace

Original post by Kavinthan

you're thick. why'd you do the higer paper if you are gonna give such b-tec answers

It is definitely the one that floats but not entirely for that reason.

Reply 324

Kavinthan

Original post by FlakeFace

It is definitely the one that floats but not entirely for that reason.

i'll explain again.
i chose nylon and polyester.

•

it had equal tensile strength

•

similar stiffness/flexibility

•

nylon was lighter but had a much higher water absorbency so when both is wet they'd be around the same weight

•

they both sink in water too

the one that floats is the weakest so each time it snaps, it will need to be replaced and al though the kevlar one is strong, the other factors isn't good enough

Reply 325

Z-Dust

Didn't Polyester and Polyethene essentially have trade offs? I thought they both were equally suitable. I don't remember the facts about nylon, though.

Reply 326

Z-Dust

Original post by Kavinthan

the one that floats is the weakest so each time it snaps, it will need to be replaced and al though the kevlar one is strong, the other factors isn't good enough

I mentioned something along the lines of this as a point too.

Reply 327

AneebMMalik

Original post by Kavinthan

you're thick. why'd you do the higer paper if you are gonna give such b-tec answers

Why would u say that?

Reply 328

Kavinthan

Original post by AneebMMalik

Why would u say that?

have you seen why i posted that
that isn't what a higher candidate will do.
apologies if the truth hurt

Reply 329

_Priyesh_

Original post by Kavinthan

have you seen why i posted that
that isn't what a higher candidate will do.
apologies if the truth hurt

An higher candidate wouldn't choose two materials when the question asks to choose the best material.

Reply 330

ShortStuff8

That test was quite straight-foward in the end. Most of the questions were concerning graphs which is fine by me. However the last 6 marker threw me because of the wording but looking back on it there was some obvious stuff I left out :frown:

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Reply 331

kxylah

hey guys, got the physics forum up and running
http://www.thestudentroom.co.uk/showthread.php?t=3327315

Reply 332

Kavinthan

Original post by _Priyesh_

An higher candidate wouldn't choose two materials when the question asks to choose the best material.

but is there anything wrong in me saying that those two are suitable polymers. just let me know what in my explanation is wrong...

Reply 333

_Priyesh_

Original post by Kavinthan

but is there anything wrong in me saying that those two are suitable polymers. just let me know what in my explanation is wrong...

In past similar questions the mark scheme only allows up to 2 marks I wrong material is chosen. May not be the case in this question due many people having different answers. I chose polypropene as it was the most lightweight, water resistant, the tensile strength may have been the lowest but it was still close to the other materials, (difference of 5). Don't remember the figures on flexibility.

Reply 334

SusamS

I put the last polymer was the best cuz although its the weakest, there is only a little difference in strength between it and the other two. Moreover, its other properties will overcompensate for this etc...

Reply 335

MØRGS

can anyone remember what they put for the uses of crude oil?

Did it have to be specific (e.g. kerosene) or general (fuels and lubricants)?

Reply 336

SusamS

Original post by MØRGS

can anyone remember what they put for the uses of crude oil?

Did it have to be specific (e.g. kerosene) or general (fuels and lubricants)?

The same question came up a few years ago, you have to put fuels and lubricants, you don't get marks for being specific as it asks for uses not examples

Reply 337

chocolatesauce

Original post by Kavinthan

the maximum marks i would have lost is 17. that is disgusting. nomesayn. know what i'm sayin

whats it for an A*?

Reply 338

MØRGS

Original post by SusamS

The same question came up a few years ago, you have to put fuels and lubricants, you don't get marks for being specific as it asks for uses not examples

Good!!! Thanks for the reply :smile:

Reply 339

username1941491

Original post by SusamS

The same question came up a few years ago, you have to put fuels and lubricants, you don't get marks for being specific as it asks for uses not examples