Answer:
The pH of a solution containing an amphetamine (with pKb of 4.2) concentration of 250 mg/l is 10.5
Explanation:
To solve the question we note that the
The mass of amphetamine = 250 mg/l
The molar mass of amphetamine = 135.2062 g/mol
Number of moles of amphetamine = (250 mg)/(135.2062 g/mol) = 1.85×10⁻³ moles
That is the initial concentration of amphetamine = 1.85×10⁻³ M
We have
therefore
Which gives 6.3×10⁻⁵
x = 0.0003116 = [OH⁻] = [C₉H₁₃NH⁺]
However x = [OH⁻] = 3.116×10⁻⁴
pOH = -log[OH⁻] = -log(3.116×10⁻⁴) = 3.506
pH = 14 - pOH
= 14 - 3.506
= 10.49
≈ 10.5
Answer:
the oxidation state of each atom
Answer:
Ca^+2
Explanation:
Hence, the correct option is A.
the balanced equation for the formation of ammonia is as follows
N₂ + 3H₂ --> 2NH₃
stoichiometry of H₂ to NH₃ is 3:2
in gases number of moles of gas is directly proportional to volume of gases.
therefore molar ratio is equal to volume ratios.
this means volume ratio of H₂ to NH₃ is 3:2
volume of H₂ reacted - 54.1 L
if 3 L of H₂ forms - 2 L of NH₃
then 54.1 L of H₂ forms - 2/3 x 54.1 = 36.1 L of NH₃
volume of NH₃ formed is 36.1 L
The amount of the solute is constant during dilution. So the mole number of HCl is 2*1.5=3 mole. The volume of HCl stock is 3/12=0.25 L. So using 0.25 L stock solution and dilute to 2.0 L.