Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 357463 times)

Offline 8T

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3000 on: June 06, 2010, 07:49:04 pm »
Know how to ask. There is nothing more difficult for some people, nor for others, easier.

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3001 on: June 06, 2010, 07:49:57 pm »
Um, in my book for cracking its 540*C :-\ and yeah typo Al2O3 ;)
450C-750C

Offline 8T

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3002 on: June 06, 2010, 07:56:22 pm »
In o/n 09 paper 32 q 6 c the total number of moles of gases why is it 0.08 i thought it would be 0.04 explain please quickly???
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Offline 8T

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3003 on: June 06, 2010, 07:58:25 pm »
Know how to ask. There is nothing more difficult for some people, nor for others, easier.

Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3004 on: June 06, 2010, 08:01:26 pm »
In o/n 09 paper 32 q 6 c the total number of moles of gases why is it 0.08 i thought it would be 0.04 explain please quickly???
first you find the moles of fe2o3 which is  .08


and thn the ration of moles of gases = 2: 1 therfore .04

and there are two gases

so . 04 + .04
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Offline 8T

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3005 on: June 06, 2010, 08:03:56 pm »
first you find the moles of fe2o3 which is  .08


and thn the ration of moles of gases = 2: 1 therfore .04

and there are two gases

so . 04 + .04
Fe2o3 is 0.04 not 0.08 .. soo?
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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3006 on: June 06, 2010, 08:06:09 pm »
Fe2o3 is 0.04 not 0.08 .. soo?
sorry i meant fe2so4

12.16 /152
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Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3007 on: June 06, 2010, 08:47:59 pm »
c)

1. 12.16/152 g= 0.08 moles

2. Molar ratio
= 2 : 1
= 0.08 : x
so x= 0.04

3. 56+56+16+16+16 = 160g

4.  moles = mass/mass of 1 mole

mass = 0.04 * 160
=6.4g

5. two gases so 0.04 + 0.04 = 0.08mol

6. vol of gas = 0.08 * 24
= 1.92

Offline $H00t!N& $t@r

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3008 on: June 06, 2010, 09:15:39 pm »
ok i have a silly question...  :-[      s05 q2c (i)  
how do u knw which one is in excess?
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Offline The InViSiBlE GIrl (Eva)

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3009 on: June 06, 2010, 09:20:09 pm »
somebody pls explain to me this...
Hey Ya could someone pls do this question its really wierd cant figure it out at all
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Offline The InViSiBlE GIrl (Eva)

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3010 on: June 06, 2010, 09:20:41 pm »
somebody pls explain to me this...
Hey Ya could someone pls do this question its really wierd cant figure it out at all
LiFe Is NoT tHe MeAsUrE oF tHe NuMbEr Of BrEaDtHs We TaKe, BuT rAtHeR oF tHe MoMeNtS tHaT tOoK oUr BrEaDtHs AwAy <3 LIFE :-D

Offline $H00t!N& $t@r

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3011 on: June 06, 2010, 09:29:49 pm »
Hey Ya could someone pls do this question its really wierd cant figure it out at all

lol wheres the question?
"If A equals success, then the formula is:
A=X+Y+Z, X is work. Y is play. Z is keep your mouth shut"- Albert Einstein

Offline The InViSiBlE GIrl (Eva)

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3012 on: June 06, 2010, 09:31:22 pm »
Hey smart guy can u pls solve this question for me really cant understand it The link is just below this line.
Quote from: CatAly$t on June 05, 2010, 07:13:46 PM

c)

1. 12.16/152 g= 0.08 moles

2. Molar ratio
= 2 : 1
= 0.08 : x
so x= 0.04

3. 56+56+16+16+16 = 160g

4.  moles = mass/mass of 1 mole

mass = 0.04 * 160
=6.4g

5. two gases so 0.04 + 0.04 = 0.08mol

6. vol of gas = 0.08 * 24
= 1.92
LiFe Is NoT tHe MeAsUrE oF tHe NuMbEr Of BrEaDtHs We TaKe, BuT rAtHeR oF tHe MoMeNtS tHaT tOoK oUr BrEaDtHs AwAy <3 LIFE :-D

Offline The InViSiBlE GIrl (Eva)

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3013 on: June 06, 2010, 09:33:05 pm »
Hey smart guy can u pls solve this question for me really cant understand it The link is just below this line.
Quote from: CatAly$t on June 05, 2010, 07:13:46 PM

c)

1. 12.16/152 g= 0.08 moles

2. Molar ratio
= 2 : 1
= 0.08 : x
so x= 0.04

3. 56+56+16+16+16 = 160g

4.  moles = mass/mass of 1 mole

mass = 0.04 * 160
=6.4g

5. two gases so 0.04 + 0.04 = 0.08mol

6. vol of gas = 0.08 * 24
= 1.92
LiFe Is NoT tHe MeAsUrE oF tHe NuMbEr Of BrEaDtHs We TaKe, BuT rAtHeR oF tHe MoMeNtS tHaT tOoK oUr BrEaDtHs AwAy <3 LIFE :-D

Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #3014 on: June 06, 2010, 09:40:43 pm »
ok i have a silly question...  :-[      s05 q2c (i)  
how do u knw which one is in excess?

OK look at the graph, mass of the plate is constant after some time. What does it mean? No more Zn is reacting, right? So the reaction is finished. Therefore Zn is excess as it is still left after the reaction is over. Got it?