AQA GCSE Chemistry - C2 & C3 (14th May 2015)

Reply 300

SmashedIt

5

Original post by Willnewman234

Can dissolve stuff I think

Posted from TSR Mobile

Thanks, what about mixes with water?

Reply 301

Clintbarton

14

Anyone else absolutely crapping it??

Reply 302

samstyan99

hey everyone,

I know everybody probably answered this question a thousand times, but honestly can't be bothered to trawl back through the forum, so basically does anybody have any idea what the 6 mark 'QWC' questions could be for Unit 2 and 3? Just worried because yesterday's Biology transect question totally threw me!

Really stressing out right now : /

Thanks

Sam

Reply 303

SmashedIt

5

Original post by Clintbarton

Anyone else absolutely crapping it??

I certainly am

Reply 304

molly2789

1

Original post by SmashedIt

Thanks, what about mixes with water?

Ethanol is a useful solvent because it mixes well with water which produces a neutral solution :smile:

Reply 305

SmashedIt

5

Original post by samstyan99

hey everyone,

I know everybody probably answered this question a thousand times, but honestly can't be bothered to trawl back through the forum, so basically does anybody have any idea what the 6 mark 'QWC' questions could be for Unit 2 and 3? Just worried because yesterday's Biology transect question totally threw me!

Really stressing out right now : /

Thanks

Sam

My teacher analysed all past papers and she predicted that the six marker on unit 2 wil be on acids+base or precipitation, and titration on unit 3

Reply 306

Clintbarton

14

https://m.youtube.com/watch?v=AHLXqGhZ1Gg also has predictions on unit three as well as good revision stuff for physics and chemistry. Explains all the maths bits well too. If you have a crappy teacher who doesn't care then this woman is brilliant lol

Reply 307

G_Head

1

Original post by molly2789

Can anyone help me out with electroplating? I know the basics but not enough for a 6 mark question on it :/

Generally

electrolysis is used
positive anode is the thing you want to plate in ie silver or gold
negative cathode is the thing you want to plate ie a goblet
the electrolyte must contain ions of the plating element ie silver or gold
this will be used to replace anode as it gets used up
the Au, for example, will form a layer on the goblet or whatever is on the cathode
it is used for make things look more attractive, and protecting them, and making them stronger

thiz should secure 6 marks if it comes up, hope this alright. Feel free to correct if anything is wrong :smile:

!

Reply 308

annalg

2

[QUOTE="Studentz001;55769171"]Good luck to you too!
I am very scared that the exam will have questions on hard and soft water. I think I know the basics, but not much on how hard water is softened and purified. Could you please help me?![/QUOTE

Water is purified by filtering it to remove solid particles then chlorine is added to kill microbes. Silver nanoparticles can also be added to kill microbes. Fluoride is added too to help prevent tooth decay. You need to know some advantages and disadvantages of chlorination and fluoridation.
Temporary hard water is softened by boiling it because the calcium hydrogencarbonate decomposes to form calcium carbonate (scale), removing the calcium ions from the water. Permanent hard water can be softened by adding sodium carbonate (washing soda) or passing it through an ion exchange column containing ion exchange resin with sodium or hydrogen ions in it, so when the water flows through the calcium or magnesium ions are replaced by the sodium or hydrogen ions so it is softened. Hope that helps!

Reply 309

samstyan99

Original post by SmashedIt

My teacher analysed all past papers and she predicted that the six marker on unit 2 wil be on acids+base or precipitation, and titration on unit 3

thanks ! I'm too stressed to do any proper revision right now, but I'll go over my titration notes on the way to school tomorrow : ) good luck!!!

Reply 310

aneesha_brat

4

Original post by Jules12345

what do we think for six marker on c2?????

Always a method of reaction

Reply 311

Amaterasu_

1

- Useful video for anyone having issues with titrations- this was really helpful and lays out titrations in a simple and easy way. [video="youtube;j_N2QU74AtM"]https://www.youtube.com/watch?v=j_N2QU74AtM[/video]

I have the feeling that the QWC will be on either electrolysis or bases, alkalis and acid reactions :smile:

This is my first post so please forgive me if the etiquette is off!

Reply 312

Emma_B1

2

Original post by samstyan99

hey everyone,

I know everybody probably answered this question a thousand times, but honestly can't be bothered to trawl back through the forum, so basically does anybody have any idea what the 6 mark 'QWC' questions could be for Unit 2 and 3? Just worried because yesterday's Biology transect question totally threw me!

Really stressing out right now : /

Thanks

Sam

I think it will be on either electroplating or making salts

Reply 313

molly2789

1

Thank you so much :smile:

Reply 314

whoopwhoop

Original post by SmashedIt

My teacher analysed all past papers and she predicted that the six marker on unit 2 wil be on acids+base or precipitation, and titration on unit 3

for the unit two one does that mean making salts equations and experiments?? :confused:

Reply 315

Nai18

2

Water is purified by filtering it to remove solid particles then chlorine is added to kill microbes. Silver nanoparticles can also be added to kill microbes. Fluoride is added too to help prevent tooth decay. You need to know some advantages and disadvantages of chlorination and fluoridation.
Temporary hard water is softened by boiling it because the calcium hydrogencarbonate decomposes to form calcium carbonate (scale), removing the calcium ions from the water. Permanent hard water can be softened by adding sodium carbonate (washing soda) or passing it through an ion exchange column containing ion exchange resin with sodium or hydrogen ions in it, so when the water flows through the calcium or magnesium ions are replaced by the sodium or hydrogen ions so it is softened. Hope that helps!

What are the advantages and disadvantages of chlorination and fluoridation?

Reply 316

Gobygaga

I found the empirical formula easy if you inderstand the basic steps. First find the mass of the atoms present and their Ar. Then divide the mass by the Ar for each. Then divide each answer through by the smallest. This gives the whole number ratio which equals the empirical formula. I know this sounds confusing but I hope it helps a bit.

Reply 317

txa98

2

I don't know how to explain titration..don't really understand it and I'm scared there will be a 6 marker on it! anyone have a simple explanation or resources??