Answer:
a) 1.71 × 10⁻³ M
b) 8.00 × 10⁻⁵ M
Explanation:
In order to calculate the solubility (S) of Pb(SCN)₂ we will use an ICE chart. We identify 3 stages (Initial, Change, Equilibrium) and complete each row with the concentration or change in the concentration.
Pb(SCN)₂(s) ⇄ Pb²⁺(aq) + 2 SCN⁻(aq)
I 0 0
C +S +2S
E S 2S
The solubility product (Ksp) is:
Ksp = 2.00 × 10⁻⁵ = [Pb²⁺].[SCN⁻]² = S . (2S)² = 4S³
S = 1.71 × 10⁻³ M
<em>b) Calculate the molar solubility of lead thiocyanate in 0.500 M KSCN.</em>
KSCN is a strong electrolyte that dissociates to give 0.500 M K⁺ and 0.500M SCN⁻.
Pb(SCN)₂(s) ⇄ Pb²⁺(aq) + 2 SCN⁻(aq)
I 0 0.500
C +S +2S
E S 0.500 + 2S
Ksp = 2.00 × 10⁻⁵ = [Pb²⁺].[SCN⁻]² = S . (0.500 + 2S)²
In the term (0.500 + 2S)², 2S is negligible.
Ksp = 2.00 × 10⁻⁵ = S . (0.500)²
S = 8.00 × 10⁻⁵ M
Answer:
Gravitational potential energy of water behind the dam
Explanation:
Energy can be defined as the ability (capacity) to do work. The two (2) main types of energy are;
a. Gravitational potential energy (GPE): it is an energy possessed by an object or body due to its position above the earth.
b. Kinetic energy (KE): it is an energy possessed by an object or body due to its motion.
Hydroelectric power plant refers to a renewable source of energy used for the generation of electricity, through the use of powerful hydraulic steam turbines operating at high voltage and are being driven by the energy acquired by water falling from a height and flowing through a penstock (pipe) i.e the mechanical energy (gravitational potential energy + kinetic energy).
At a hydroelectric power plant, potential energy is changed into kinetic energy. The kinetic energy is then transformed into electrical energy.
The source of the energy that turns the turbine in the power plant is Gravitational potential energy of water behind the dam, usually from streams or rivers.
Answer:
Copper and aluminium nitrate
Explanation:
The reaction is a simple redox reaction. Where copper ions are reduced to copper atoms and the aluminium atoms oxidized to aluminium ions.
The equation for the reaction is as follows:
2Al₍s₎ + 3Cu(NO₃)₂₍aq₎ ⇒ 2Al(NO₃)₃ + 3Cu₍s₎
The ionic equation:
2Al₍s₎ + 3Cu²⁺₍aq₎⇒2Al³⁺₍aq₎ + 3Cu₍s₎
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:
Explanation:
The first two are easy:
H2O, H3O+ and OH- all exist in an equilibrium
[H3O+] = [OH-] = 10^-7 M
HCl is a strong acid so 1M of it will disassociate completely
[H3O+] = [Cl-] = 1 M
The third one is also an equilibrium as HNO2 is a weak acid. Ka is given so [HNO2] and [NO2-] can be calculated.
The fourth one is a buffer solution so its pH can be looked up to give the concentrations.