Math

posted by Yasemine Monday, May 13, 2013 at 10:33pm.

We have an important chemsitry test due and I want to make sure that I do not mess up on my algebra. I am dealing with the integrated rate law, but my question is purely algebraically in nature. I hope, somebody can help me.

1) ln(A) = -kt+ln(B)

solve for t
solve for k
solve for B

2) 1/(B) = kt + 1/(B)

solve for k
solve for t
solve for B

Thank you so much for your help. It is greatly appreciated

• Math - Reiny Monday, May 13, 2013 at 10:45pm

  1)
  ln(A) = -kt+ln(B)
  kt = lnB - lnA
  kt = ln(B/A)
  t = ln(B/A) / k
  
  k = ln(B/A) / t
  
  lnB = lnA + kt
  B = e^(lnA + kt)
  
  2)
  1/B = kt + 1/B
  0 = kt
  t = 0
  or
  k = 0
  B is any value except B≠0
  (are you sure you have no typo in 2) ?

• Math - Yasemine Monday, May 13, 2013 at 10:50pm

  2) should be 1/(B) = kt+1(A)
  I am dealing with concentrations and A and B are just placeholders for the concentrations.
  Thanks

• Math - Reiny Monday, May 13, 2013 at 11:00pm

  2) I thought there was something wrong with your first typing of the question
  
  1/B = kt + 1/A
  multiply each term by AB, the LCD
  A = ABkt + B
  A - B = ABkt
  t = (A-B)/(ABk)
  k = (A-b)/(ABt)
  
  from: A = ABkt + B
  A = B(Akt + 1)
  B = A/(Akt + 1)