the ammonia/ammonium buffer system is used to optimize polymerase chain reactions (pcr) used in dna studies. the equilibrium for this buffer can be written as nh4+(+(aq)+nh3(aq) calculate the ph of a buffer that contains 0.045 m ammonium chloride and 0.095 m ammonia. the ka of ammonium is 5.6×10? 10. express your answer using two decimal places.

The pH of the buffer system is 9.57

Explanation:

Step 1: Data given

Molarity of NH4Cl = 0.045 M

Molarity of NH3 = 0.095 M

Ka of ammonium is 5.6*10^-10

 pKa = -log (5.6 * 10^-10) = 9.25

Step 2: The balanced equation

NH4+(aq) ⇆ H+(aq) + NH3(aq)

Step 3: Calculate the pH of the buffer

pH = pKa + log[NH3]/[NH4+]

pH = 9.25 + log(0.095/0.045)

pH = 9.57

The pH of the buffer system is 9.57

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally