Kb = [HA} [OH-] / [A-] where [A-] represents the concentration of CN- (.068M)
Kb = Kw / Ka = 1 x10-14 / 4.9 x 10-10 = 2 x 10-5
Since this is a salt solution which could be considered to have formed from the neutralization of a strong base (NaOH) and a weak acid (HCN), the Na+ will have no effect on the pH of the solution while the CN- ion will undergo hydrolysis:
CN- + H2O --> HCN + OH-
Based on this equation, the quantities of HCN and OH- produced must be the same and therefore [HCN]=[OH-]. We will set this equal to x.
Plugging into the original equation yields:
2 x 10-5 = x2 / .068 M
Solving for x yields 1.2 x 10-3 whidh is equal to the [OH-]
The pOH then is equal to -log (1.2x10-3) = 2.9
The pH of the solution would be 14 - 2.9 = 11.1
To answer this, we use Raoult's Law where the partial pressure is equal to the product of the fraction of the gas in the mixture and its total pressure. Also, we use Dalton's Law of Partial Pressure where the total pressure is equal to the sum of the partial pressure of the gases in the mixture.
Ptotal = 73.44 + 128.52 + 2.04 = 204 atm
201.96 = x (204)
x = 0.99
Most biomolecules are organic compounds, and just four elements—oxygen, carbon, hydrogen, and nitrogen—make up 96% of the human body's mass.
The correct answer is, tobacco.
<span>Answer:
CuX = Cu2+ + X2-
Ksp = [Cu2+] * [X2-]
for each mole of CuX that dissolves we get x mol of each of the anions and cations
Ksp = x^2 = 1.27 x 10 ^-36
x= 1.13 x 10 ^-18 moles of CuX per liter of pure water
if the solution has [Cu2+]= 0.27 M
Ksp becomes x ( x + 0.27)
as we can see above x is extremely small so can be ignored inside the brackets
0.27 x = 1.27 x 10^-36
x = 1.27 x 10^-36 / 0.27 = 4.70 x 10 ^-36 moles per liter
In 0.19M X2- we have
Ksp = 0.19x = 1.27 x 10^-36
x = 1.27 x 10^-36 / 0.19 = 6.68 x 10 ^-36 moles per liter</span>