POST YOUR BIO AND CHEM PAPER 1 DOUBT HERE !!!!

[Ahmed Khider]

Chemistry MCQ doubt:​

​

Q: In some countries, ethanol, rather than petrol, is used as a fuel for cars. Which gas is not present in the exhaust from cars that burn ethanol?​

​

A Carbon dioxide​

B Nitrogen​

C Oxides of nitrogen​

D Sulphur dioxide​

Is the answer D??

 

[thats_me]

Thank u for ur reply.. hmm I still dont get it We can take any atom ryt? Coz it doesn't say an atom from group 0! So if we take magnesium as atom X (proton no. 12) & Calcium as atom Y (12+8 = 20).. they are in different groups & also not unreactive..

Actually in the ques the just gave suggestions
We have to answer for which suggestions can be correct
So student 2 took a noble gas and gave his suggestion while student 1 did not tak a noble gas, so both of them are correct
It CAN be unreactive & it CAN be in the same grp
Calcium & Magnesium are in the same group..

 

[thats_me]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w09_qp_12.pdf
Number 14.
Can anyone explain this please ?

Em not very sure..
I think NaOH forms so at the negative electrode it turns blue/purple & at anode forms chlorine so it becomes colourless (bleached)

 

[Rahma Abdelrahman]

Em not very sure..
I think NaOH forms so at the negative electrode it turns blue/purple & at anode forms chlorine so it becomes colourless (bleached)

Yes, you are right!

 

[Rahma Abdelrahman]

Is the answer D??

Yes, D ....

 

[Maz]

Em not very sure..
I think NaOH forms so at the negative electrode it turns blue/purple & at anode forms chlorine so it becomes colourless (bleached)

I thought the same thing too,but the ms says it's B.
Red at the anode and purple at the cathode.

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Assalam-o-alaikum wr wb...
just want to 'confirm' one answer..

​

 

[saroooor]

Chemistry MCQ doubt:​

​

Q: In some countries, ethanol, rather than petrol, is used as a fuel for cars. Which gas is not present in the exhaust from cars that burn ethanol?​

​

A Carbon dioxide​

B Nitrogen​

C Oxides of nitrogen​

D Sulphur dioxide​

Could give me the year ?

 

[thats_me]

I thought the same thing too,but the ms says it's B.
Red at the anode and purple at the cathode.

Oh :O i din check the ms :S

 

[saroooor]

Assalam-o-alaikum wr wb...
just want to 'confirm' one answer..

View attachment 12432​

Is the answer B ?!

 

[thats_me]

I thought the same thing too,but the ms says it's B.
Red at the anode and purple at the cathode.

No it says D
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w09_ms_12.pdf q14

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Is the answer B ?!

i also think it's B cuz only iodide changes to nitrate...but the answer sheet i am having, it's written C in it but i am pretty sure Potassium nitrate won't react with lead (II) nitrate...

Jazakallah Khair anyway

 

[Rahma Abdelrahman]

I thought the same thing too,but the ms says it's B.
Red at the anode and purple at the cathode.

MS says D!

 

[Maz]

Is the answer B ?!

Yup, B

 

[thats_me]

Yes, D ....

But sulphur dioxide is not formed in car exhaust rite?

 

[Rahma Abdelrahman]

But sulphur dioxide is not formed in car exhaust rite?

It is normally formed when any fuel containing sulfur is burnt, so I guess petrol contains SO2.
But, from our knowledge, we should conclude that ethanol doesn't have sulfur.

 

[saroooor]

i also think it's B cuz only iodide changes to nitrate...but the answer sheet i am having, it's written C in it but i am pretty sure Potassium nitrate won't react with lead (II) nitrate...

Jazakallah Khair anyway

assalaim alaikum wr wb
Could you give me the year ?

 

[Maz]

No it says D
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w09_ms_12.pdf q14

Oops! sorry. Checked the wrong one.
By the way why does the ms have the title 0625 Accounting.

 

[thats_me]

It is normally formed when any fuel containing sulfur is burnt, so I guess petrol contains SO2.
But, from our knowledge, we should conclude that ethanol doesn't have sulfur.

Oh alright! thankyuh!

 

[thats_me]

Oops! sorry. Checked the wrong one.
By the way why does the ms have the title 0625 Accounting.

Lol :S where :O its chem