Physics, Chemistry and Biology: Post your doubts here!

[thats_me]

hi,
i have a couple of questions in oct/nov 1998
Q.4
Q.21
Q.11
tyvm and plz help
http://www.freeexampapers.com/past_papers.php?l=Past_Papers/IGCSE/Chemistry/CIE/1993-2003/ here is the link again

4 : u need to estimate like if u take 1 division for 0.5 u'll get 35.5 so i'll be B
11 : It will be A ,as it has 4 hydrgen in one carbon so 4 water molecules
if u c B it has 2 carbon with 6 hydrgen so 6 water molecule but if u take 2 of the structures of A u will get 8 H which is 8H2O
21: i think it will be C but em not sure

 

[kainat husain]

hey question for chemistry
which side of periodic table alkalis, non metals, metals, and acids lie
and if its a metal will it have a positive charge or negative charge!
please explain

 

[Abu mota]

4 : u need to estimate like if u take 1 division for 0.5 u'll get 35.5 so i'll be B
11 : It will be A ,as it has 4 hydrgen in one carbon so 4 water molecules
if u c B it has 2 carbon with 6 hydrgen so 6 water molecule but if u take 2 of the structures of A u will get 8 H which is 8H2O
21: i think it will be C but em not sure

21 the answer is D :/
and i dont understand the type of question in 4 cud u explain it further plz, how do u know the scale?
Also 11 didnt understand too srry but ur answers for 4 and 11 are correct btw

 

[thats_me]

hey question for chemistry
which side of periodic table alkalis, non metals, metals, and acids lie
and if its a metal will it have a positive charge or negative charge!
please explain

Look,
Left side has metals which have either basic or amphoteric oxides (grp1 are called alkali metals) basicity increases to the left and down the group
Right side has non-metals which have either acidic or neutral oxides, Acidity increases to the right and up the group
Charges: Metals usually loose electron( which are negativel charged) becoming positively charged
non-metals on the other hand gain electron becoming negatively charged

 

[kainat husain]

Look,
Left side has metals which have either basic or amphoteric oxides (grp1 are called alkali metals) basicity increases to the left and down the group
Right side has non-metals which have either acidic or neutral oxides, Acidity increases to the right and up the group
Charges: Metals usually loose electron( which are negativel charged) becoming positively charged
non-metals on the other hand gain electron becoming negatively charged

woow mashALLAH u r soo good believe me u r gonna a* pray for me nd thnxxxxxxxxxxxxx

 

[Roselian]

Quick question

What are the reactions of ammonia and its salts?

 

[thats_me]

21 the answer is D :/
and i dont understand the type of question in 4 cud u explain it further plz, how do u know the scale?
Also 11 didnt understand too srry but ur answers for 4 and 11 are correct btw

 

[thats_me]

woow mashALLAH u r soo good believe me u r gonna a* pray for me nd thnxxxxxxxxxxxxx

Thankyuhhh!!! Inshallah! sure

 

[Abu mota]

View attachment 11930
View attachment 11931

tyvm i really appreciate ur very very hard work i understood them all now
inshallah you get A* in every subject u take

 

[thats_me]

tyvm i really appreciate ur very very hard work i understood them all now
inshallah you get A* in every subject u take

Inshallah the same will be with u thankyuh! n ur Most welcum

 

[kainat husain]

Here
View attachment 11758
27 : Magnesium + carbon --> Magnesium Carbonate
where as Cooper oxide + carbon ---> Copper + carbondioxide
and Carbondioxide turns lime water milky

for question 27 its even MAGNESIUM OXIDE? s

 

[thats_me]

for question 27 its even MAGNESIUM OXIDE? s

which ques was this?

 

[Abu mota]

which ques was this?

it is may/june 2007 and the answer is magnesium cannot be reduced by carbon but the other metal can be reduced by carbon

 

[thats_me]

it is may/june 2007 and the answer is magnesium cannot be reduced by carbon but the other metal can be reduced by carbon

Aite thx

 

[Ahmed Khider]

Hey guys could anyone explain to me why in s06 paper 1 chemistry the answer to question 9 is c??

 

[xxxt]

Hey guys could anyone explain to me why in s06 paper 1 chemistry the answer to question 9 is c??

b/c diagram 2 shows a single bond which may represent hydrgen
n diagram 3 shows double bond which may represent oxygen
but diagram 1 shows no bond which means dat its a noble gas and water can never be made of noble gas
so the answer is 2 and 3

 

[Abu mota]

Hey guys could anyone explain to me why in s06 paper 1 chemistry the answer to question 9 is c??

because water is made up of hydrogen and oxygen. and hydrogen is diatomic with single bonds so 2 and also oxygen is diatomic but it has double bonds as oxygen has a valency of two and this is 3 and so the answer is 2 and 3 which is C
if u dont understand ask again

 

[xxxt]

hey question for chemistry
which side of periodic table alkalis, non metals, metals, and acids lie
and if its a metal will it have a positive charge or negative charge!
please explain

metals are on the left side of the periodic table
non metals are on the right side of the table
you can not exactly say where acids and alkalies lie (it depends wether u are considering elements or compounds)
but metalic elements usually form alkali compounds
while non metalic elements form acidic compounds.

 

[Ahmed Khider]

b/c diagram 2 shows a single bond which may represent hydrgen
n diagram 3 shows double bond which may represent oxygen
but diagram 1 shows no bond which means dat its a noble gas and water can never be made of noble gas
so the answer is 2 and 3

Thx alot i appreciate it

 

[Ahmed Khider]

because water is made up of hydrogen and oxygen. and hydrogen is diatomic with single bonds so 2 and also oxygen is diatomic but it has double bonds as oxygen has a valency of two and this is 3 and so the answer is 2 and 3 which is C
if u dont understand ask again

Well i understand it thx alott. If i didnt understand it i wouldnt hve asked u again becoz it sounds rude to me