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chemistry questions..hope u all stop by :)

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AS-Girl:
hey guys
i just had few chemistry questions i couldn't solve! I would appreciate all the help I can get :)


1) How many ions per formula unit would you find if you dissolve (NH4)2 [Ce(NO3)6] in water?
a) 3    b) 9   C) 2    d)6


2)For baking soda, NaHCO3. What is the molar ratio of C to O? (i got confused between (b) and (d) :-\)
a) 1:1        b) 3:1   c) 1:2     d) 1:3



3) lemon juice has a [H+] of 0.01 M. What is the [OH-]?
a) 1.0 x 10^-14 M
b)1.0 x 10^-7 M
c)1.0 x 10^- 12 M
d)1.0 x 10^2 M



That's all..Thanks in advance ;)

NotAbod:

--- Quote from: AS-Girl on April 03, 2011, 06:32:55 pm ---2)For baking soda, NaHCO3. What is the molar ratio of C to O? (i got confused between (b) and (d) :-\)
a) 1:1        b) 3:1   c) 1:2     d) 1:3



--- End quote ---

i am not an AS student but i think i can only help with question 2
ratio of C to O is 1 to 3, because each 3 oxygen atoms are bonded to 1 carbon atom, ( 1 C atom and 3 O atoms)
according to this, ratio C to O should be 1 Carbon to 3 Oxygen
Answer D
sorry i could'nt answer 1 and 3 cuz i didnt understand them ( i am an IGCSE student)
correct me please if i am wrong, i am not sure from the answer
~AboD

Monopoly:

--- Quote from: AS-Girl on April 03, 2011, 06:32:55 pm ---3) lemon juice has a [H+] of 0.01 M. What is the [OH-]?
a) 1.0 x 10^-14 M
b)1.0 x 10^-7 M
c)1.0 x 10^- 12 M
d)1.0 x 10^2 M


--- End quote ---

try using solubility product of water, Kw. Kw =  [H+][OH-]

 At 25oC, Kw= 1.0x10-14

thus [OH-]= kw /[H+] = 1.0x10-14/0.01

AS-Girl:
hey abod
i'm not sure whether u compare O with C or C with O! lets get more opinions! (anyways thanks for ur try..appreciate it ;))


Thanks Monopoly..i totally understood the idea!!


one question left :D

elemis:

--- Quote from: AS-Girl on April 04, 2011, 12:04:45 pm ---hey abod
i'm not sure whether u compare O with C or C with O! lets get more opinions! (anyways thanks for ur try..appreciate it ;))


Thanks Monopoly..i totally understood the idea!!


one question left :D

--- End quote ---

The question says the molar ratio of C is to O..... pretty self-explanatory.

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