Homework Help Forum: chem

Posted by help! on Monday, February 16, 2009 at 4:12pm.

A new potential heart medicine, code-named X-281, is being tested by a pharmaceutical company, Pharma-pill. As a research technician at Pharma-pill, you are told that X-281 is a monoprotic weak acid, but because of security concerns, the actual chemical formula must remain top secret. The company is interested in the drug's value because only the dissociated form of the chemical is active in preventing cholesterol buildup in arteries. To find the of X-281, you prepare a 0.079 test solution of X-281. The pH of the solution is determined to be 3.00. What is the of X-281?

• chem - DrBob222, Monday, February 16, 2009 at 4:17pm

  You need to re-read your post an fill in the missing blanks. For example, two lines from the bottom: To fin the ???????of X-281, you ...... So it would help if we knew what we were looking for. Another example, last line: What is the ?????of X-281?

  
  

• chem - help!, Monday, February 16, 2009 at 4:28pm

  A new potential heart medicine, code-named X-281, is being tested by a pharmaceutical company, Pharma-pill. As a research technician at Pharma-pill, you are told that X-281 is a monoprotic weak acid, but because of security concerns, the actual chemical formula must remain top secret. The company is interested in the drug's Ka value because only the dissociated form of the chemical is active in preventing cholesterol buildup in arteries. To find the pKa value of X-281, you prepare a 0.079M test solution of X-281. The pH of the solution is determined to be 3.00. What is the pKa of X-281?

  
  

• chem - DrBob222, Monday, February 16, 2009 at 5:12pm

  HA ==>H^+ + A^- Ka = (H^+)(A^-)/(HA) Convert pH of 3.00 to (H^+). Plug in that value for (H^+) and (A^-) and for (HA) plug in 0.079-(H^+). solve for Ka, then for pKa. Post your work if you get stuck.

  
  

• chem - xyz, Sunday, February 22, 2009 at 12:13am

  Is the concentration of A^- just 0.079 then?

  
  

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