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ALL CIE CHEMISTRY DOUBTS HERE !!

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$!$RatJumper$!$:

--- Quote from: Ari Ben Canaan on October 09, 2010, 03:09:16 pm ---Watch videos on youtube.

--- End quote ---

Can you please provide me a link to get started?

Freaked12:
Am i late  :o

What the heck

moles CO2 = 0.352 g / 44.009 g/mol=0.00800
moles H = 2 x 0.072 /18.02 g/mol=0.00800

Freaked12:
MgH2 is Mg 2+ and 2 H- ions so oxidation No of Mg = +2 (Group 2 - loses 2 electrons to form Mg2+ ion 2 -2 empties outer shell)

AlH3 is Al3+ + 3 H- ions so oxidation number of Al = +3 (Group 3 - loses 3 electrons to form Al3+ ion 3 - 3 empties outer shell)

PH3 Is P3- and3 H+ so oxidation number of P = -3 (Group 5 - gains 3 electrons to form P3- ion : 5 + 3 = 8 fills up outer shell)

H2S is 2 H+ and S2- ions so oxidation number of S is -2 (Group 6 - gains 2 electrons to form S2- ion ; 6 + 2 = 8 fills up outer shell)



Sorry
Just wanted to get involved

moon:

--- Quote from: Deadly_king on October 09, 2010, 05:13:44 am ---Nan Ari......the data provided is sufficient to find the answer.

CxHy + (x + y/4)O2 ----> xCO2 + (y/2) H2O

Number of moles CO2 = Mass / Mr = 0.352/44 = 0.008

Number of moles of H2O = 0.072/18 = 0.004

1 mole of the hydrocarbon gives 0.008 moles of CO2 and 0.004 moles of H2O

Therefore from equation above we can note that x = 0.008 while y/2 = 0.004

Empirical formula will hence be C8H8


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why didn't we find the mole ratio CO2: H2O
so that the formula can be C2H2...

moon:
for nov 2009 ppr 2

The oxidation state of hydrogen in the metal hydrides is always -1 so why in PH3 the oxidation state is +1 and hence x+3(-1)=0 so x=+3 really need help..Thanks n advance

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