chemistry help

[Ghost Of Highbury]

okk..a doubt in reduction and oxidation

1) C4H8 + 6O2 --> 4CO2   +   4H2O

is this reduction, oxidation or reduction and why?

i strongly think that it is oxidation as oxygen is added...however, the oxidation state of "oxygen" decreases from -4 to -6

so its redox...
plzz..helpp!!

2.) 2KNO3=2KNO2+O2
      
   this equation is so messed up for oxidation states


    there are three elements in 1 compund ...how do u determine the oxidation states for them

plzz help!! is it oxidation reduction or redox..(plz explain the reason too!


thanks a lot!!
    

[nid404]

I'll break it up and explain

1) In C4H8
H has ox.state +1 on each...so +1
the overall charge on the compound is 0
so C has ox.state -2

In 602
the ox.state is 0

Products
In 4CO2
C goes on to become +4 and O2 becomes -2

and H remains as +1 and O -2

it is redox becuz Cs ox.state has increased and that of oxygen has decreased
You do take into account the ox.state of oxygen

[Ghost Of Highbury]

I'll break it up and explain

1) In C4H8
H has ox.state +1 on each...so +1
the overall charge on the compound is 0
so C has ox.state -2

In 602
the ox.state is 0

Products
In 4CO2
C goes on to become +4 and O2 becomes -2

and H remains as +1 and O -2

it is redox becuz Cs ox.state has increased and that of oxygen has decreased
You do take into account the ox.state of oxygen

understood everything...

only..H becomes +2 na as its H2O
and...O2 becomes -4 na as it is O2

[nid404]

second one

in KNO3
NO3 is ionic
so overall charge is -1
K is +1 and O3 is -6
so N is +5....+5-6=-1..overall charge becomes zero with K as +1
ok so

their states change to
NO2 again ionic with -1 charge
N becomes +3 since it is O2 and O2 is -4 overall
K remains as +1

and ox.state of O2 becomes 0
so Oxygen's ox.state increased but that of N decreased
so it's redox again

I've tried my best to explain

[nid404]

I'll break it up and explain

1) In C4H8
H has ox.state +1 on each...so +1
the overall charge on the compound is 0
so C has ox.state -2

In 602
the ox.state is 0

Products
In 4CO2
C goes on to become +4 and O2 becomes -2

and H remains as +1 and O -2

it is redox becuz Cs ox.state has increased and that of oxygen has decreased
You do take into account the ox.state of oxygen

understood everything...

only..H becomes +2 na as its H2O
and...O2 becomes -4 na as it is O2

yaa if u mean the overall charge

[Ghost Of Highbury]

second one

in KNO3
NO3 is ionic
so overall charge is -1
K is +1 and O3 is -6
so N is +5....+5-6=-1..overall charge becomes zero with K as +1
ok so

their states change to
NO2 again ionic with -1 charge
N becomes +3 since it is O2 and O2 is -4 overall
K remains as +1

and ox.state of O2 becomes 0
so Oxygen's ox.state increased but that of N decreased
so it's redox again

I've tried my best to explain

thanks a lot~
just 1 qestion...is the charge of the NO3 and NO2 --> -1

if so ...how did u get that?...
soo..if its SO4...is the oxidation state overall -2??

[nid404]

second one

in KNO3
NO3 is ionic
so overall charge is -1
K is +1 and O3 is -6
so N is +5....+5-6=-1..overall charge becomes zero with K as +1
ok so

their states change to
NO2 again ionic with -1 charge
N becomes +3 since it is O2 and O2 is -4 overall
K remains as +1

and ox.state of O2 becomes 0
so Oxygen's ox.state increased but that of N decreased
so it's redox again

I've tried my best to explain

thanks a lot~
just 1 qestion...is the charge of the NO3 and NO2 --> -1

if so ...how did u get that?...
soo..if its SO4...is the oxidation state overall -2??

this is a general rule
In an ion, the sum equals the overall charge

[Ghost Of Highbury]

thought so..

tks a lot!!

u sure both r redox..

because astar told me that the 1st one is oxidation and the 2nd one is reduction...??@?@?@?

[nid404]

thought so..

tks a lot!!

u sure both r redox..

because astar told me that the 1st one is oxidation and the 2nd one is reduction...??@?@?@?

i just did redox yesterday...so according to my AS textbook..it's redox
but i'll ask my teacher tom and let you know if it's 200% redox or not..