Physics, Chemistry and Biology: Post your doubts here!

Rahma Abdelrahman

Rahma Abdelrahman

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AAnsarii said:
w09_qp11 q4 http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w09_qp_11.pdf
if u c d periodic tbl, atomic no goes(4 noble gases): 2,8,18,36.... 18 & 36 have a diff of 18 n not 8, so it could b ne option
same grp should b ticked, but i dnt think unreactive ... plz help

sm ppr q20
Click to expand...

Firstly, Atomic no. goes 2, 10, ....(not 8).
Secondly, it is a fact that noble gases are all unreactive, the Question says: Which students CAN be correct? so it is just a suggestion; it may be right or wrong!
For Q.20, answer is A because barium sulfate and silver chloride are formed which are both insoluble and form precipitates.
Any further doubt ? (y)
 
thats_me

thats_me

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AAnsarii said:
do v need 2 learn d reactivity series 4 metals? plz say no
Click to expand...
do it this way :D
metals :
Please(potassium) stop(sodium) calling(calcium) my(magnesium) aunt(aluminium) carol(carbon) zine(zinc) inanimate(iron) things(tin) like(lead) honey(hydrogen) comb(copper) sugar(silver) goey(gold) plop(platinum)
non-metals :
FAther (flourine)of (oxygen)carol(chlorine) brother(Bromine) naughty(nitrogen) sister(sulphur) idiot(iodine) parents(phosphorus) called(carbon) home(hydrogen) :p
 
Abu mota

Abu mota

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AAnsarii said:
w09_qp11 q4 http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w09_qp_11.pdf
if u c d periodic tbl, atomic no goes(4 noble gases): 2,8,18,36.... 18 & 36 have a diff of 18 n not 8, so it could b ne option
same grp should b ticked, but i dnt think unreactive ... plz help

sm ppr q20
Click to expand...
idk if anyone answered u yet, but for Q.4 it says which can be correct and so if u start with already a noble gas and moved 8 protons u will also end up with a noble gas and so it will be unreactive and will be in the same group and also atomic number is 2 then 10 then 18, i guess ur periodic table is wrong.
for Q.20 it is B because sulfuric acid contains sulfate ions and adding barium chloride is actually the test for sulfates (it makes white precipitate) hydrochloric acid doesnt contain sulfate ions and so there is no effect.
 
Rahma Abdelrahman

Rahma Abdelrahman

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thats_me said:
do it this way :D
metals :
Please(potassium) stop(sodium) calling(calcium) my(magnesium) aunt(aluminium) carol(carbon) zine(zinc) inanimate(iron) things(tin) like(lead) honey(hydrogen) comb(copper) sugar(silver) goey(gold) plop(platinum)
non-metals :
FAther (flourine)of (oxygen)carol(chlorine) brother(Bromine) naughty(nitrogen) sister(sulphur) idiot(iodine) parents(phosphorus) called(carbon) home(hydrogen) :p
Click to expand...

Is the reactivity series of non-metals in our syllabus?
 
AAnsarii

AAnsarii

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Rahma Abdelrahman said:
Firstly, Atomic no. goes 2, 10, ....(not 8).
Secondly, it is a fact that noble gases are all unreactive, the Question says: Which students CAN be correct? so it is just a suggestion; it may be right or wrong!
For Q.20, answer is A because barium sulfate and silver chloride are formed which are both insoluble and form precipitates.
Any further doubt ? (y)
Click to expand...
jazakillah, if i have ne, will iA post it here. jazakillah again(y)
 
Abu mota

Abu mota

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GorgeousEyes said:
Chemistry .
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for Q.36 it is D u need to memorize the structures of all hydrocarbons, it cant be explained :/
for Q.40 it is D also because u need to memorize the conditions of the reactions u take, none of these questions can be explained, it can only be memorized :)
 
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