CHEM AND BIO HELP AND TIPS HERE

[Vin]

plz answer my folowin Q

in june  2007 ,Q11 , y the no. of atome is 8 y not 9  

oh and in Q 3 same year , y it is 75.5 not 84.5  

plz help

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 ??

[haris94]

plz answer my folowin Q

in june  2007 ,Q11 , y the no. of atome is 8 y not 9 

oh and in Q 3 same year , y it is 75.5 not 84.5 

plz help

q3) each small division is 0.5 (there r 20 divisions between 2 big lines...so 10/20=0.5)
the mercury is at 5.5
so it cant be 84.5

q11) ethanoic acid -- ch3cooh
2 carbon + 4 hydrogen + 2 oxygen
total=2+4+2=8

[Ghost Of Highbury]

plz answer my folowin Q

in june  2007 ,Q11 , y the no. of atome is 8 y not 9  

oh and in Q 3 same year , y it is 75.5 not 84.5  

plz help

CH3COOH - 1+3+4 = 8

2Cs, 4H, 2O

ok check vin's post, better explanation

[jellybeans]

QUESTION!

i thought you get CaO + CO₂ from heating Lime?
help..?

[Ghost Of Highbury]

QUESTION!

i thought you get CaO + CO₂ from heating Lime?

You get CaO and CO2 from heating Calcium Carbonate, not lime

Lime = CaO

Calcium Carbonate = CaCO3

[jellybeans]

You get CaO and CO2 from heating Calcium Carbonate, not lime

Lime = CaO

Calcium Carbonate = CaCO3

OHHHHH, THANKS!

[CatAly$t]

see if this helps u ..

http://www.chem.ucalgary.ca/courses/351/laboratory/drying%20agents.pdf

thx.it does help me....

[Ghost Of Highbury]

OHHHHH, THANKS!

Anytime.

[The Golden Girl =D]

A@di i stil didn't get Q 3  

 i kno i'm askin alot but plz help lol

i also have this

same year Q16   

[Vin]

A@di i stil didn't get Q 3 

do you get this ??

https://studentforums.biz/index.php/topic,1411.msg221498.html#msg221498

[Vin]

thx.it does help me....

ok ur welcome

[Ghost Of Highbury]

this drove me crazy during my IGCSEs too..

S + 02 --> S02

S - oxidation number 0..
O2 - oxidation number 0

SO2 --> oxidation number of O = (-2*2) = -4 , thus oxidation number of S = +4

S--> 0 to 4 oxidation
O -> 0 to -4 reduction

thus redox.

2S02 + 02-->2 S03

2SO2 -> oxidation number of O = (-2*2) = -4, thus S = +4.  O2 -> 0, final of O = -4+0 = -4

SO3--> Oxidation number of O = (-2*3) = -6, of S = +6

Final , S --> 4 to 6 oxidation

         O --> -4 to -6 reduction

SO3 + H20--> H2SO4

SO3 --> O = (-3*2) = -6 , thus S = +6

H2O --> O = -2, thus H = +2

O in both compounds thus, final number of O = -6-2 = -8

H2SO4--> O = (-2*4) = -8, thus H = +2, as final oxidation number of the compound shud be 0, -8+2+S = 0

thus, S = +6

now the changes

S --> 6 to 6
H --> 2 to 2
O --> -8 to -8..

NOt redox.

[Vin]

Redox reactions, or oxidation-reduction reactions, have a number of similarities to acid-base reactions. Redox reactions are concerned with the transfer of electrons between species. Like acid-base reactions, redox reactions are a matched set -- you don't have an oxidation reaction without a reduction reaction happening at the same time. Oxidation refers to the loss of electrons, while reduction refers to the gain of electrons.

OIL RIG
oxidation is loss of electrons
reduction is the gain of electrons

@Aadi .. i was looking for this one u've posted .. as usual u got me

[Ghost Of Highbury]

@Aadi .. i was looking for this one .. as usual u got me

lol its k, she has to understand the oxidation/reduction numbers too...that concept is very important..

[jellybeans]

ummmmm.. :/ lol how are we supposed to solve that question? :p