Answer:
pH = 10.38
Explanation:
∴ molar mass C9H13N = 135.21 g/mol
∴ pKb = - log Kb = 4.2
⇒ Kb = 6.309 E-5 = [OH-][C9H20O3N+] / [C9H13N]
∴ <em>C</em> sln = (205 mg/L )*(g/1000 mg)*(mol/135.21 g) = 1.516 E-3 M
mass balance:
⇒ <em>C</em> sln = 1.516 E-3 = [C9H20O3N+] + [C9H13N]......(1)
charge balance:
⇒ [C9H20O3N+] + [H3O+] = [OH-]; [H3O+] is neglected, come from water
⇒ [C9H20O3N+] = [OH-].......(2)
(2) in (1):
⇒ [C9H13N] = 1.516 E-3 - [OH-]
replacing in Kb:
⇒ Kb = 6.3096 E-5 = [OH-]² / (1.516 E-3 - [OH-])
⇒ [OH-]² + 6.3096 E-5[OH] - 7.26613 E-8 = 0
⇒ [OH-] = 2.3985 E-4 M
∴ pOH = - Log [OH-]
⇒ pOH = 3.62
⇒ pH = 14 - pOH = 14 - 3.62 = 10.38
Answer:
Number of moles = 2.89 mol
Explanation:
Given data:
Number of moles of sugar = ?
Mass of sugar = 990 g
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of C₁₂H₂₂O₁₁:
12× 12 + 22×1.008 + 16×11 = 342.2 g/mol
Number of moles = 990 g / 342.2 g/mol
Number of moles = 2.89 mol
Steps:
Mw = w * R * T / p * V
T = 88 + 273 => 361 K
p = 975 mmHg in atm :
1 atm = 760 mmHg
975 mmg / 760 mmHg => 1.28 atm
Therefore:
= 0.827 * 0.0821 * 361 / 1.28 * 0.270
= 24.51 / 0.3456
molar mass = 70.92 g/mol
Answer:
An electron will jump to a higher energy level when excited by an external energy gain such as a large heat increase or the presence of an electrical field, or collision with another electron.
Explanation:
hope it helps you
