Chemistry Doubts: Paper 1 & 2

[sourov97]

it has been about 15-17 days since i 'registered'. i started posting from the day just before chem atp dont look at the likes recieved - they are useless, u can get enough of them by posting jokes. message count can give u a 'faint' idea in this case...many just post "thanks" as reply which are also counted...
join threads, share problems & answers and u will learn soon.

 

[tdk]

thanks for explaining. one more pls: Q 28 http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s07_qp_1.pdf

Ca, Mg, and Zn are more reactive than hydrogen, so H can't displace oxygen from their oxides. But Cu is less reactive than H, so it can displace Cu from CuO and form water.. The colorless liquid in the U-tube is water.
ANSWER: B

 

[achana]

well thank -u a lot i'll get hold of it now ~!!!

it has been about 15-17 days since i 'registered'. i started posting from the day just before chem atp dont look at the likes recieved - they are useless, u can get enough of them by posting jokes. message count can give u a 'faint' idea in this case...many just post "thanks" as reply which are also counted...
join threads, share problems & answers and u will learn soon.

 

[UFO_far_planet]

Ca, Mg, and Zn are more reactive than hydrogen, so H can't displace oxygen from their oxides. But Cu is less reactive than H, so it can displace Cu from CuO and form water.. The colorless liquid in the U-tube is water.
ANSWER: B

it's Cu alright, but "But Cu is less reactive than H, so it can displace Cu from CuO and form water." isn't fully right. Fe is more reactive than hydrogen, but H2 CAN reduce FeO.
Basically, any metal oxide below zinc can be reduced by H2.

 

[Snowysangel]

Okay so hydrogen and sulfur dioxide are reducing agent and all halogens are oxidising agents (apart from the potassium compounds)...is that right? Oh and calcium chloride and concentrated sulfuric acid are drying agents

 

[inquisitiveness]

7. methane - from decay of vegetaions - contributes to global warming.

what is decomposition of vegetation

 

[sourov97]

what is decomposition of vegetation

decaying of plants when they die!

 

[hela]

Please help with the following questions:
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_12.pdf
Q23 Q36
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_11.pdf
Q13 Q22
Thanks in advance..

 

[Kamihus]

Please help with the following questions:
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_12.pdf
Q23 Q36
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_11.pdf
Q13 Q22
Thanks in advance..

This thread is in O-level section
You should post it in A-Level section