CHEM AND BIO HELP AND TIPS HERE

[Ghost Of Highbury]

VIN , plz  look again at what u wrote ...ur talkin abt hydration ....while baladya is talkin abt crackin

Ethane --> Ethene + Hydrogen

Cracking.

[Baladya]

VIN, but when do we know if h2 is coming out and when do we know an alkene is coming out?

[jellybeans]

i copied the wrong question

opsi daizy

hahahaha.. isn't that a displacement reaction? lol, ><
metal X displaces Y cuz its more reactive..? no? :/

[The Golden Girl =D]

http://www.freeexampapers.us/IGCSE/Chemistry/CIE/2009%20Nov/0620_w09_qp_11.pdf

I don't understand Q23, why have they chosen 2 and 3 only?

copper is below hydrogen in the reactivity series ...it can't displace Hydrogen ..therefore ..no reaction ..hence 2 and 3 only 

[Baladya]

Ethane --> Ethene + Hydrogen

Cracking.

Octane ---> Hexane + ethene
Thats what the book says... so when is it an alkene and when hydrogen?

[Vin]

    H    H                           H    H
     |    |        (steam)         |     |
H- C - C - H   ---------->    C = C    +   H₂
     |    |        (>800 *C)      |     |
     H    H                           H     H

ETHANE                             ETHENE      HYDROGEN


 

VIN , plz  look again at what u wrote ...ur talkin abt hydration ....while baladya is talkin abt crackin

Nop .. im 100% sure .. ethane cracks to give ethene and hydrogen .. which IS cracking

[Vin]

Octane ---> Hexane + ethene
Thats what the book says... so when is it an alkene and when hydrogen?

     H    H                           H    H
     |    |        (steam)         |     |
H- C - C - H   ---------->    C = C    +   H₂
     |    |        (>800 *C)      |     |
     H    H                           H     H

ETHANE                             ETHENE      HYDROGEN


 

[WARRIOR]

hahahaha.. isn't that a displacement reaction? lol, ><
metal X displaces Y cuz its more reactive..? no? :/

BOTH ARE METALS !!

METAL OXIDE IS A BASE

METALS DONT REACT WITH METAL OXIDE :/

[Ghost Of Highbury]

i copied the wrong question

opsi daizy

B?

@baladya - Hydrogen from cracking, erm. Ethane --> Ethene + Hydrogen , this is the only way ..

one more , but no hydrogen, cracking though

Decane --> pentane + ethene + propene

[Lariemeeva]

@the golden girl: Right, thanks for the answer, what about Q13, why is the UI colourless for OH-?

[Raywin]

ethanoic acid - CH₃COOH count them they are eight

Q3 if u look at the scale of the therm. it has 10 divisions for 5 *C and the mercury is showing something5.5 .. i'll show u on the diag. itself gimme 1 min

HAS IT BECOME TOO COMPLICATED ??

oK GUYS I really DONT GET THE q3 THE thermometer one... :S PLEASE help...

[Ghost Of Highbury]

BOTH ARE METALS !!

METAL OXIDE IS A BASE

METALS DONT REACT WITH METAL OXIDE :/

huh??

Another example of 'competition' between metals to form compounds is observed in the reaction between metals and metal oxides.

Observe the reaction between iron and copper oxide, mixed and heated strongly.

http://www.s-cool.co.uk/gcse/chemistry/metals--the-reactivity-series/displacement-reactions-and-the-reactivity-series.html

[Vin]

VIN, but when do we know if h2 is coming out and when do we know an alkene is coming out?

depends on the alkane .. actually in only the one i hav mentioned..  hydrogen "comes out "

[Moonlyte]

Do they provide us with the reactivity series list in chemistry paper 1 igcse?

[Baladya]

B?

@baladya - Hydrogen from cracking, erm. Ethane --> Ethene + Hydrogen , this is the only way ..

one more , but no hydrogen, cracking though

Decane --> pentane + ethene + propene

I think i understand whats wrong...

When its craking of things like Ethane, hydrogen is gonna be the product
When its cracking of Octane, Decane, bla bla its alkene that is the product