IGCSE CHEMISTRY 2013 (May 20th & June 10th)

I actually found that chemistry exam quite challenging!

I disagree. My notes for the electrolysis of water say in big capital letters "GRAPHITE ELECTRODES ARE NEVER USED - PLATINUM IS USED INSTEAD". But it depends what they accept. I put for the oxygen question that it is slightly soluble so dissolves in water.

I said about the greenhouse gases released but also the fact that no buildings will have to be built in order to burn the bags so there would be no trees or habitats destroyed

It's says in the student book that 'carbon is frequently used for electrodes because it is chemically inert'.

I wrote that oxygen was soluble in water too, so that's a relief. Thanks.

The only thing that really annoyed me about that paper, is that no triple topics came up?! All the revision I have done since the last paper seems to have been for nothing...

Also, how do you remove red dye from rose petals?

I wrote carbon should be used as the electrodes. So is it correct?

Yea it is correct and about why there is less oxygen collected there are two possible answers:
. Oxygen reacts with the electrodes to form carbon dioxide
. Oxygen is soluble in water.
i wrote the latter.

I know, there was nothing on the processes/alcohols/any conditions etc. I think it's dissolving.

Oh so is it possible to say that it reacts with the electrode?

Even I wrote that. Can u confirm the answer for ?1 :
. Filtration
. Simple distillation
. Dissolving
. Paper...
. Fractional distillation

Yea it is correct and about why there is less oxygen collected there are two possible answers:
. Oxygen reacts with the electrodes to form carbon dioxide
. Oxygen is soluble in water.
i wrote the latter.

Even I wrote that. Can u confirm the answer for ?1 :
. Filtration
. Simple distillation
. Dissolving
. Paper...
. Fractional distillation

Can't you also use simple distillation for separating ethanol and water

They're the answers I got

For the plastic bag question I chose A because:
. Burning the bags releases greenhouse gases which is increases the rate of global warming.
. Also the plastic bags can be recycled as companies take spare bags from landfills thus it doesn't harm the environment.
Although I am not sure of my 2nd point.

For the plastic bag question I chose A because:
. Burning the bags releases greenhouse gases which is increases the rate of global warming.
. Also the plastic bags can be recycled as companies take spare bags from landfills thus it doesn't harm the environment.
Although I am not sure of my 2nd point.

What was the answer for 'why couldn't sodium hydroxide be used'? I wrote because then it would be a neutralisation reaction, is that right even though I didn't talk about the fizzing