Impure substance, because pure would be dirt from the earth
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:
The partial pressure of oxygen is 52 kPa.
Explanation:
We apply Dalton's law, according to which the sum of the partial pressures of the gases that make up a gaseous mixture is equal to the total pressure of this:
Ptotal = P N2 + P C02 + P 02
300 kPa= 200kPa + 48 kPa + P 02
P 02= 300 kPa - 200kPa - 48 kPa= <em>52 kPa</em>
Answer:
The activation energy of the reaction is 1.152 kJ/mol.
Explanation:
Activation energy is the minimum amount which is absorbed by the reactant molecules to undergo chemical reaction.
Initial temperature of reaction =
Final temperature of reaction =
Initial rate of the reaction at 100 k =
Final rate of the reaction at 200 k =
Activation energy is calculated from the formula:
R = Universal gas constant = 8.314 J/ K mol