Edexcel CHEMISTRY DOUBTS!!!!

[Weaam]

Question 17



1gram of ethane = 0.03448 moles

Using above equation :

0.03448 moles * 8.314 * T  / p ; 0.28669*T/p

Doing the same thing for the others you should be able to determine the answer.

Dude, i havent the slightest clue what you did here.

I really need help on this question.

[elemis]

Dude, i havent the slightest clue what you did here.

I really need help on this question.

You need to use PV = nRT

The Ideal gas equation.

Keep plugging in the required values and see where it gets you.

P = pressure

V = volume

n = no. of moles

R = 8.314 (constant)

T = temperature in Kelvin.

I have to sleep now. Sorry. 

[Weaam]

Or i can multiply the number of moles by 24 to get the volume ?
Anyway, one last thing, Q23 c) (i) in January 09, i dont get how its done? why 0.01/2.00 * 100 is multiplyed by 2 ?

[The Golden Girl =D]

Or i can multiply the number of moles by 24 to get the volume ?
Anyway, one last thing, Q23 c) (i) in January 09, i dont get how its done? why 0.01/2.00 * 100 is multiplyed by 2 ?

As for Q 17 :

for A is going to be (12*2) + 6 = 30
   B is 2*16 = 32
   C is 2*19 = 38
   D is just 20

n=M/Mr  when Mr DECREASES, the Number of Moles INCREASES .

As for 23 , I don't get it too 

Hmm could you help me with Jan 2009 Q 11 , I don't get it AT ALL

[Weaam]

As for Q 17 :

for A is going to be (12*2) + 6 = 30
   B is 2*16 = 32
   C is 2*19 = 38
   D is just 20

n=M/Mr  when Mr DECREASES, the Number of Moles INCREASES .

As for 23 , I don't get it too 

Hmm could you help me with Jan 2009 Q 11 , I don't get it AT ALL

Q11? simple, 50cm³ of 2H₂ reacts with 25cm³ of O₂ to 2H₂O use the mole and volume ratios 2:1:2 , 50:25:50.

[The Golden Girl =D]

Q11? simple, 50cm³ of 2H₂ reacts with 25cm³ of O₂ to 2H₂O use the mole and volume ratios 2:1:2 , 50:25:50.

Ooh  Okay , thanks =]

[The Golden Girl =D]

As for Q 17 :

for A is going to be (12*2) + 6 = 30
   B is 2*16 = 32
   C is 2*19 = 38
   D is just 20

n=M/Mr  when Mr DECREASES, the Number of Moles INCREASES .

Vol = N* Mr , hence the Vol increases too

As for 23 , I don't get it too  

Hmm could you help me with Jan 2009 Q 11 , I don't get it AT ALL

Me doing it right now  

for the balance thingy I got it Right Alhamdulilah but for the second idk y I didn't -.-

Anyways it is solved as follows :

%error = positive or negative 0.01/2.01 *100 = positive or negative 0.498

% can NEVER be negative o.0 hence o.498 +0.498 = 0.996  rounded to =1 % which according to the MS is Right

MEASURING CYLINDER :

I did it as positive or negative 0.5/30 * 100 = positive or negative 1.67 %
  which is the answer But I have NO idea y not 1.67 + 1.67 = 3.34 % as the FINAL answer

Hope I helped =]

[MKh]

who iz preparing 4 edexcel A2 unit 6B?... m preparing 4 it so cud any1 suggest me hw do i began or hw shud i sufficiently prepare 4 it? Thanks in advance

[Deadly_king]

who iz preparing 4 edexcel A2 unit 6B?... m preparing 4 it so cud any1 suggest me hw do i began or hw shud i sufficiently prepare 4 it? Thanks in advance

Do you mind let me know what chapter is unit 6B because am not a student of EDEXCEL.

[MKh]

unit 6B iz d A2 alternative to practical paper (for international candidates) like 3B iz d AS alternative to practical paper...but i need help in preparing for unit 6B...any1???

[The Golden Girl =D]

Can Someone Please solve the attached papers and explain the details FULLY

Thanks In Advance =]

one sec

[elemis]

Can Someone Please solve the attached papers and explain the details FULLY

Thanks In Advance =]

one sec

no papers attached.

[The Golden Girl =D]

This stupid computer , it never works EFFT !

Anyways Hmm here are the Qs :

First it says :

delta H of Combustion of Carbon (solid state) = -394
carbon monoxide (gas state) = - 283

Hmm the Eqn as follows :

C(graphite) + 0.5 O 2 (gas) -> CO (gas)

use the data , find the Delta H of formation of carbon monoxide using Hess's Cycle .


and then the second part says :
Suggest why is it Impossible to find enthalpy change of carbon monoxide Directly ?

I wrote because it has other products as well , is that right o.0 ?!

MS's ANS : (Some) CO2 is Always produced in the reaction .

SECOND Q:

Natural Gas consists of Methane .when methane burns completely in oxygen the reaction occurs as shown below :

Bleh bleh

Methane does NOT burn Unless Lit

then A Q says :

Use this Information to explain the difference between thermodynamic and kinetic Stability

Even when the teacher explained ,I didn't Quite get it *sigh*

[Amii]

^Hc of C =^Hf + ^Hc of CO
-394=^Hf + (-283)
-394 + 283 = ^Hf
-111kj mol -1 =^Hf

[The Golden Girl =D]

^H1=^Hf + ^H2
-394=^Hf + (-283)
-394 + 283 = ^Hf
-111kj mol -1 =^Hf

Yet Again I did a Silly Mistake in this One , can u sort of look at the rest Please :S