Chemistry SPM

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[Announcements] [Introduce Yourself] [ICT] [Prasekolah] [LINUS] [KSSR] [UPSR] [PMR] [SPM] [STPM] [School] [Classroom] [Clubs & Uniformed Bodies] [JPN] [SPA] [SICT] [SPP] [SPS] [SPPK] [SPSPK] [SPI] [SPsK] [JNJK] [PPD] [Program] [Computer & Internet] [Let's Hear It From You] [Membergroup]

[Law Yew Wooi]

I need the help of the chem tchr here... i just want a confirmation regarding the answer i had written.

I just want to ask about the essay for conversion of iron (II) and iron (III). Can i use magnesium strip? Or must use magnesium powder? I wrote magnesium strip, so is it correct? And then.. if I din add excess bromine to the solution, is it correct? I just wrote Add a few drops of bromine water to the iron (II) sulphate solution.. is it correct?

For paper 3, why there is a sudden change in the format? I was shocked. For the explanation how acid causes coagulation of latex. I wrote the acid will neutralise the negative charges on the rubber molecule. This will cause the rubber molecules to come together and collide with each other. This will cause the rubber particles in the rubber molecules to break free and entangle with the rubber particles of other rubber molecules. Thus, coagulation of latex occurs. Is that correct coz i know that my terms all wrong already, but then the concept is there, will they still give marks?

And for the one which is does not contain acid and alkali, they ask why will it coagulate? Then i just wrote that there are bacteria that will carry out bacterial activity. The bacterial activity will produce acid which neutralises the acid..... and the following explanation is like the above. I remembered wrongly. I wrote carbonic acid, in fact it is lactic acid. Will they still give marks? I forgot to write the latex is exposed to air.

And why the latex with ethanoic acid will coagulate faster than the latex without any acid. I wrote because the acid produced by the bacterial activity is less concentrated and less amount than ethanoic acid. So, ethanoic acid will have higher concentration of hydrogen ions to neutralise the negative charges. Is this correct?

For the operational definition for coagulation of latex.. i wrote coagulation of latex is when the latex changes from liquid (colloid) to solid in the presence of acidic medium and is prevented by the presence of alkaline medium. Is this answer appropriate?

Sorry for asking so many questions. But i just want a confirmation whether my answers that i had written in spm are correct or not. The other questions i have no problem tackling them. Thank you very much for your kind help.

[Law Yew Wooi]

I doubt where all the chem teachers are.........
What should we write for observation for paper 3?

[Ang Wen Kai]

i think most teacher holiday le..........
school holiday most teacher don't care about engkabang le...

[Law Yew Wooi]

owh..icic.. hahahah

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