CHEM AND BIO HELP AND TIPS HERE

[Helium]

Thanks Vin,
Looks like it's a long story

[Ghost Of Highbury]

hahaha I do know this. It's the stuff we use to mess around with the lab's chemicals when the teacher is busy ..

Just one final thing (really sorry to disturb today), in oct/nov 01 in question 13, why is it not A (P only)

canu post the paper plz? and abt the unsaturated thingy

Its A or C. It cant be C because C is an acid and it wudnt be neutral. Alchol in water will be neutral

[Vin]

lol same here, our students act like 9 year old, take the syringes and start spraying water at
each other.

Are u sure the anw is A.
Q)which Group 7 element is produced at which anode.

1 solution has Molten lead(II) bromide. Bromine gas produced at P.

2 solution concentrated hydrochloric acid. Chlorine is supposed to be formed at R.

I think it should be B (P and R)

Or chloride ions dont move in concentrated solutions

i think he asked why is is not A
can u post the options too ?? i dont seem to get the paper ,, u made my life easy tho by posting the ques .. u are right .. its both

[Vin]

Thanks Vin,
Looks like it's a long story

LOL .. someone had asked me earlier i thought i'd post everything .. so tht u dont hav the same doubts

[Vin]

canu post the paper plz? and abt the unsaturated thingy

Its A or C. It cant be C because C is an acid and it wudnt be neutral. Alchol in water will be neutral

yup if u r talking about

Some body prove it's A.(plz)

It's unsaturated because it has a double bond, but why form neutral solution
in water. It has OH group which is alcohols.

[the_grim_reaper]

lol same here, our students act like 9 year old, take the syringes and start spraying water at
each other.

Are u sure the anw is A.
Q)which Group 7 element is produced at which anode.

1 solution has Molten lead(II) bromide. Bromine gas produced at P.

2 solution concentrated hydrochloric acid. Chlorine is supposed to be formed at R.

I think it should be B (P and R)

Or chloride ions dont move in concentrated solutions

Yeah it is B ohhh sh*t!!! I forgot chlorine is an element of group 7! AHHHHHHHHHH. I mean everything is correct then suddenly I do something very stupid. Don't ever get 40. Either it's 39 or 38.. I hate myself......

[Ghost Of Highbury]

Okay, good luck everyone, do well.

[Vin]

Yeah it is B ohhh sh*t!!! I forgot chlorine is an element of group 7! AHHHHHHHHHH. I mean everything is correct then suddenly I do something very stupid. Don't ever get 40. Either it's 39 or 38.. I hate myself......

i know ..same happens to me .. i messed up one question in my mock .. we got the winter 09 paper .. same ditto with no changes .. i lost one mark there .. wish i would hav solved tht paper before .. would hav got full !!

[princess12]

WHAT IS SOLOUBLE AND INSOLUBLE SALT
CAN ANY 1 TELL ME
 PLAESE  

[7ooD]

can someone explain this fast in may june 2009 chemistry paper 1 q 6 it says the electronic configuration of an ion is 2,8,8 wat could this ion be it gave me a table with right and wrong for S 2-   CA 2+  and choose both why???

[Vin]

WHAT IS SOLOUBLE AND INSOLUBLE SALT
CAN ANY 1 TELL ME
 PLAESE  

soluble salt is FULLY miscible in water .. and leaves no precipitation in the tube ..

insoluble salt DOES NOT 'mix' with water or not soluble and leaves some precipitate behind  

[Ghost Of Highbury]

WHAT IS SOLOUBLE AND INSOLUBLE SALT
CAN ANY 1 TELL ME
 PLAESE  

-All Chlorides, bromides and iodides are soluble except lead chloride/bromide/iodide, silver Cl/Br/I, and mercury Cl/Br/I

-All sulphates are soluble except lead sulphate, barium sulphate and calcium sulphate

-All carbonates are insoluble except Sodium, potassium (All group 1 metals in general) and ammonium carbonates, which are soluble.

-All hydroxides are insoluble except Sodium, potassium(All group 1 metals in general), ammonium, calcium, strontium and barium hydroxides, which are soluble.

-All nitrates are soluble


heres the list

[the_grim_reaper]

i know ..same happens to me .. i messed up one question in my mock .. we got the winter 09 paper .. same ditto with no changes .. i lost one mark there .. wish i would hav solved tht paper before .. would hav got full !!

That happens at your place too??? HAHAHAHA lol. Our teacher tried to be extra clever so he mixed nov 09 gce with igcse nov 09. HAHAH but we had already LEARNED all the answers in both of em' . 90% of the class got 40 .

[Ghost Of Highbury]

can someone explain this fast in may june 2009 chemistry paper 1 q 6 it says the electronic configuration of an ion is 2,8,8 wat could this ion be it gave me a table with right and wrong for S 2-   CA 2+  and choose both why???

Sulfur - 16

2,8,6 if it gainst 2 electrons, 2,8,8

Calcium - 20

2,8,8,2 if it loses 2 electrons , 2,8,8

[Vin]

can someone explain this fast in may june 2009 chemistry paper 1 q 6 it says the electronic configuration of an ion is 2,8,8 wat could this ion be it gave me a table with right and wrong for S 2-   CA 2+  and choose both why???

ok the electronic config. of
Ca = 2,8,8,2
S   =2,8,6

so when Ca loses both e- and S gains 2 e- they form 2,8,8 or ions
Ca has the valency of +2
S has the valency of -2

so, A