orgo chem plz help me

• 

  lovely_allie

  
  February 23rd 2010, 2:16 pm

• When a solution of sodium hydroxide is added to a solution of ammonium carbonate and is heated, ammonia gas, NH3, is released. Write the net ionic equation for this reactiọn Both NaOh and (Nh4)2CO3 exist as dissociated ions in aqueous solution?

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  8cùi_bắp

  
  February 23rd 2010, 2:29 pm

• i think it's general chemistry question
  
  i'm not sure but maybe like this :
  
  
  
  

• 

  lovely_allie

  
  February 23rd 2010, 2:39 pm

• I think u are correct. Thanks so much. I have two more problems that i don't get though.
  
  What is the molarity of a solution made by dissolving 3.4g of Ba(OH)2 in enough water to make 450 ml of solution?
  
  Assume that Ba(OH)2 ionizes completely in water to Ba2+ and OH- ions. What is the ph of the solution?
  
  Please help..
  Thanks.

• 

  8cùi_bắp

  
  February 23rd 2010, 2:39 pm

• hahaha i forget balance the equation
  
  NaOH + (NH4)2 CO3 ---> Na + 2 CO3 + 2 NH3 + H20

• 

  Lòng Trắc Ẩn

  
  February 23rd 2010, 2:40 pm

• .. homework nhiều quá ..

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  8cùi_bắp

  
  February 23rd 2010, 2:49 pm

• molarity is mol/L, right?
  if it is right, then you need to convert the 450 mL to L (V)
  find the MM(molar mass= g/mol) of Ba(OH)2
  
  3.4g x ( 1/MM) x ( 1/V) = molarity
  see the units cancel out
  
  3.4g (mol/g) x (1/L) = mol/L

• 

  lovely_allie

  
  February 23rd 2010, 2:58 pm

• thanks I got it.

• 

  8cùi_bắp

  
  February 23rd 2010, 3:00 pm

• i forget the part how to find pH
  but you should right down the reaction of Ba(OH)2
  Ba(OH)2 → Ba + 2OH
  and the OH should be 1/2 Ba(OH)2 i guess
  then find the pOH
  => pH= 14-pOH

• 

  lovely_allie

  
  February 23rd 2010, 3:03 pm

• I don't get it. What do u mean by the Oh should be 1/2 Ba(OH)2 ?

• 

  katkatt

  
  February 23rd 2010, 3:06 pm

• lovely_allie wrote:I don't get it. What do u mean by the Oh should be 1/2 Ba(OH)2 ?

  
  
  Allie, see the equation of dissociation of Ba (OH)2, 1 molecule Ba will be equal 2 molecule OH

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  lovely_allie

  
  February 23rd 2010, 3:08 pm

• yeah I see that. But how can u find the ph from that equation?
  
  Thanx.

• 

  lovely_allie

  
  February 23rd 2010, 3:09 pm

• oh I got it..thanks..again.

• 

  lovely_allie

  
  February 23rd 2010, 3:11 pm

• Thanks so much.....
  
  Last one.
  
  The usual concentration of HCO3- ions in blood plasma is approximately 24 millimoles per/ L (mmol/L). How would you make up 1.00 L of a solution containing this concentration of HCO3- ions?

• 

  8cùi_bắp

  
  February 23rd 2010, 3:15 pm

• lovely_allie wrote:I don't get it. What do u mean by the Oh should be 1/2 Ba(OH)2 ?

  
  
  you're right .. OH should be Ba(OH)2 not 1/2 Ba(OH)2 cuz Ba(OH)2 ionizes completely in water ..
  
  i'm thinking abt another pH problem that the solution is not ionized completely

• 

  lovely_allie

  
  February 23rd 2010, 3:21 pm

• can you assist me with the last problem? I have an hr before the hw is due and it's being grade.
  Thanks.