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Chemistry Help HERE ONLY !!

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heat619:

--- Quote from: kam on May 31, 2009, 06:05:13 pm ---
--- Quote from: asus on May 31, 2009, 05:34:44 pm ---u guys...help me with this question..
ppr3 june 04 7 b) ii

--- End quote ---

can someone answer tht
i need help with that too

--- End quote ---

to find which is in excess we have to compare moles and see which one has more, this will be excess.
Moles of Mg=3/24=0.125
Moles of Ethanoic acid= 12/60=0.2
So now u may think that ethanoic acid is excess.
But look at the mole ratios in the formula, it says (1)Mg + 2 ethanoic acid
so u hav to divide moles of acid by 2 so u get 0.1, so with the same ratios, mg has more mole(0.125),so its in excess....

kam:
i was talking about bii
how many moles of hydrogen formed

and thx By the way
+rep 4 u

evilzurg307:
Can any one explain the answer to O/N 2008 q4(a)(iii)??

4(a)(iii)Name two compounds (other than sodium hydroxide) that would react with benzoic acid to form sodium benzoate?
A: Sodium oxide and Sodium Carbonate but why???

kam:
acid+base= salt + water
acid+carbonate=salt + water +carbon dioxide
as the oxide is basic
the salt is sodium benzoate
gettit?
i just hope im right
correct me if im wrong tho

heat619:

--- Quote from: kam on May 31, 2009, 06:23:32 pm ---i was talking about bii
how many moles of hydrogen formed

and thx By the way
+rep 4 u

--- End quote ---


ohh srry lol
k, use mole ratio, if 2 moles gave u 0.2 mol, then 1 mole would give u X
X= (0.2*1)/2
X=0.1 :D

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