IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => GCE AS & A2 Level => Queries => Topic started by: yasser37 on November 16, 2010, 09:11:41 am

Title: Chemistry MCQs
Post by: yasser37 on November 16, 2010, 09:11:41 am

Hi guys
Happy Eid


so my exam is on Friday

I used  to have problems with organic chem questions but I think am good now with those

My problem is now with Halogens and Calculations

is there a summary for halogens or something? like reactions with AgNo3 or So2- and also their oxidizing ability and stuff like that which can be easy to remember?

As for calculations:
Sometimes they ask questions about Combustion of organic compounds and ask us to find it's formula and sometimes they'd give us masses and stuff like that. What's the approach I should take there?

any tips are appreciated

Thanks

Title: Re: Chemistry MCQs
Post by: elemis on November 16, 2010, 09:26:09 am

Quote

Sometimes they ask questions about Combustion of organic compounds and ask us to find it's formula and sometimes they'd give us masses and stuff like that. What's the approach I should take there?

I think you are referring to combustion analysis.

See this for more info : http://preparatorychemistry.com/Bishop_Combustion_Analysis.htm

Title: Re: Chemistry MCQs
Post by: Deadly_king on November 16, 2010, 11:45:01 am

Quote from: yasser37 on November 16, 2010, 09:11:41 am

My problem is now with Halogens and Calculations

is there a summary for halogens or something? like reactions with AgNo3 or So2- and also their oxidizing ability and stuff like that which can be easy to remember?

Try here (http://www.chemguide.co.uk/organicprops/haloalkanemenu.html#top).

The important thing about reaction of halogenoalkane with AgNO3 is that it forms :
i) white precipitate of AgCl when the halogen present is Chlorine.

ii) cream precipitate of AgBr when the halogen present is Bromine.

iii) yellow precipitate of AgI when the halogen present is Iodine.

Quote from: yasser37 on November 16, 2010, 09:11:41 am

As for calculations:
Sometimes they ask questions about Combustion of organic compounds and ask us to find it's formula and sometimes they'd give us masses and stuff like that. What's the approach I should take there?

I doubt that you'll get these since combustion of hydrocarbons was the first number in paper 2. ;)

Title: Re: Chemistry MCQs
Post by: Hypernova on November 16, 2010, 12:14:44 pm

The BEST SUMMARY EVER attached

Title: Re: Chemistry MCQs
Post by: yasser37 on November 17, 2010, 08:36:41 am

Thanks to everyone for the help

@ Hypernova


do u have more of these

they're great man