chemistry unit 2 aqa thread

Original post by rumana101

does it gain 3 electrons?

gains - 1 mark
3 electrons- 2 marks

Reply 81

electrahearts

15

this thread is so helpful! my chemistry teacher didn't tell us anything about exam technique :frown:

Reply 82

Original post by Terrydaktal

gains - 1 mark
3 electrons- 2 marks

woo

Reply 83

warty_toe

1

Original post by bethanystephens_

how are you all feeling
what do you think the 6 marker will be this year?

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Most people think that the Six marker is going to be on forming salts. But I hope it's electrolysis of Brine. :tongue:

Reply 84

what do we need to know about thermosoftning and thermosetting polymers?

Reply 85

spnlove

3

For the useful products from electrolysis of brine, is it just chlorine makes bleach and plastics and sodium hydroxide is alkali which makes soap? Is there anything else I need to know? What can the hydrogen be used for?

Reply 86

does anyone know all we need to know about making salts?

Reply 87

ell57

1

Can someone please explain what a lattice is please?

Reply 88

Original post by spnlove

For the useful products from electrolysis of brine, is it just chlorine makes bleach and plastics and sodium hydroxide is alkali which makes soap? Is there anything else I need to know? What can the hydrogen be used for?

as a fuel

Reply 89

spnlove

3

Original post by rumana101

what do we need to know about thermosoftning and thermosetting polymers?

Thermosoftening polymers: Made from individual tangled chains held together with weak intermolecular forces (no crosslinks). As they don't have crosslinks, the forces between the chains are really easy to overcome so it melts easily. When it cools it hardens into a new shape. You can melt and remould these as many times as you like.

Thermosetting polymers: Have strong intermolecular forces (crosslinks) between the polymer chains which hold the chains firmly together. This is why it doesn't soften when heater making the polymers strong,hard and rigid.

Does anyone know if low density polythene is a thermosoftening polymer and HD polythene is a thermosetting polymer or are they completely different?

Reply 90

Loop Zoop

I'm feeling like a single blade of grass, you never know what is in the box of Chocolates.

Your Friend
L.Zoop

Reply 91

spnlove

3

Original post by rumana101

does anyone know all we need to know about making salts?

On another thread, the three methods were described, here's the link:
http://www.thestudentroom.co.uk/showthread.php?t=3314383&page=8&p=55756897#post55756897

Reply 92

dumb cabbage

Can someone explain the entire C2 pls?

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Reply 93

dumb cabbage

I'm joking but can someone actually explain me chromatography and gas chromatography?

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Reply 94

Original post by rumana101

what do we need to know about thermosoftning and thermosetting polymers?

yes, thermosoftening do not have cross links between the chains of monomers therefore they can melt
thermosetting have crosslinks so they do not melt

thermosoftening are not ideal for packaging hot food as it would melt.

(edited 8 years ago)

Reply 95

Original post by dumb cabbage

I'm joking but can someone actually explain me chromatography and gas chromatography?

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chromatography is the art of dipping chromatography paper into a solvent and leaving it so it joust touches the solvent and leaving it , the colours begin to travel up the page and the coloured compound with the least mass will travel further than the others, one can determine wht compunds are in substances by seeing the distance it travelled and the colour

gas chromatography is quicker and more accurate,
-gas carries the compounds
-in a column
-separates the compounds
-the compounds travel at different speeds
-one can determine what the compounds are due to the speed etc

Reply 96

Original post by spnlove

Thermosoftening polymers: Made from individual tangled chains held together with weak intermolecular forces (no crosslinks). As they don't have crosslinks, the forces between the chains are really easy to overcome so it melts easily. When it cools it hardens into a new shape. You can melt and remould these as many times as you like.

Thermosetting polymers: Have strong intermolecular forces (crosslinks) between the polymer chains which hold the chains firmly together. This is why it doesn't soften when heater making the polymers strong,hard and rigid.

Does anyone know if low density polythene is a thermosoftening polymer and HD polythene is a thermosetting polymer or are they completely different?

or to be more specific, the chains are chains of monomers

Reply 97

dumb cabbage

Original post by Terrydaktal

chromatography is the art of dipping chromatography paper into a solvent and leaving it so it joust touches the solvent and leaving it , the colours begin to travel up the page and the coloured compound with the least mass will travel further than the others, one can determine wht compunds are in substances by seeing the distance it travelled and the colour

gas chromatography is quicker and more accurate,
-gas carries the compounds
-in a column
-separates the compounds
-the compounds travel at different speeds
-one can determine what the compounds are due to the speed etc

Omg that's so helpful thanks :smile:

erm could you explain bases please?

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Reply 98

Chardevs

1

In need of desperate help..

somebody plesse explain to me the basics of salts e.g what is a precipitate and different methods of making different salts

Reply 99