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CHemistyr :Excess Reagent!!

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J.Darren:
https://studentforums.biz/index.php/topic,8469.msg251999.html#msg251999

1 Si is bonded to 4O
1 O is bonded to 2Si

H  COOCH3
  C
H  H

Ivo:

--- Quote from: JD46 on June 04, 2010, 04:45:10 pm ---okie dokie, here  a question  nid

1)3.0g of magnesium was added to 12.0g of ethanoic acid.
 
 Mg + 2CH3COOH ? (CH3COO)2Mg + H2
  
The mass of one mole of Mg is 24 g.
  The mass of one mole of CH3COOH is 60 g.
  (i) Which one, magnesium or ethanoic acid, is in excess? You must show your
  reasoning.[3] MJ04

P.S.I got some more doubts hope ya dont mind! ;D
-How to do i draw the humongous struucture of Sio2
-And how  would i draw the polymer of the following structure? the picture is attached.

--- End quote ---

Most of your doubts has been answered before:


--- Quote from: Ivo on June 04, 2010, 12:40:43 pm ---7) b) i) Moles of Mg = 3/24 = 0.125
           Moles of CH3COOH = 12/60 = 0.200
           Using ratios given in the equation, to compare, divide 0.2/2 = 0.100 moles of CH3COOH.          
           Therefore, magnesium is in excess.

Got it?

--- End quote ---

For Silicon Dioxide, see below.

nid404:

--- Quote from: JD46 on June 04, 2010, 04:45:10 pm ---okie dokie, here  a question  nid

1)3.0g of magnesium was added to 12.0g of ethanoic acid.
 
 Mg + 2CH3COOH ----> (CH3COO)2Mg + H2
  
The mass of one mole of Mg is 24 g.
  The mass of one mole of CH3COOH is 60 g.
  (i) Which one, magnesium or ethanoic acid, is in excess? You must show your
  reasoning.[3] MJ04

--- End quote ---

Mole Ratio of Mg to CH3COOH is 1:2
3g of Mg= 3/24 =0.125 moles
so theoretically moles of CH3COOH should be twice = 0.25
12g of CH3COOH= 12/60= 1/5 moles=0.2 moles
So CH3COOH is lesser than the theoretical value. Hence Mg is in excess

JD46:
Thanks a ton guys for the over whelming response!

-By the way, how do i polymerise the structure
-and the ususal, naming the blessed alkane's,alkene's isotopes, and  forming their structure and  drawing,..basically im  in structural problems!!  ;D :D :D

Thanks  frnds!!

elemis:
As all IGCSE chemistry exams are over, this topic will be locked.

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