If you start with 0.30 m Mn₂ , at 12.5 pH, free Mn₂ concentration be equal to 4.6 x 10⁻¹¹ m
Initial molarity of Mn₂ = 0.30 M
Final molarity of Mn₂ = 4.6 x 10⁻¹¹
pH = ?
Ksp [Mn(OH)₂] = 4.6 x 10⁻¹⁴ (standard value)
Write the ionic equation
Mn(OH)₂ → Mn⁺² + 2OH⁻
[Mn⁺²] = 4.6 x 10⁻¹¹
We will calculate the concentration of OH⁻ by using Ksp expression
Ksp = [Mn⁺²][OH-]²
[Mn⁺²][OH⁻]² = 4.6 x 10⁻¹⁴
[OH⁻]² = 4.6 x 10⁻¹⁴ / 4.6 x 10⁻¹¹
[OH⁻]² = 10⁻³
[OH⁻] = (10⁻³)¹⁽²
[OH⁻] = 0.0316 M
Calculate the pOH
pOH = -log [OH⁻]
pOH = -log [0.0316]
pOH = 1.5
Now calculate pH
pH = 14 - pOH
pH = 14 - 1.5
pH = 12.5
You can also learn about molarity from the following question:
brainly.com/question/14782315
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Answer:
= 0.238 L
Explanation:
From the given information:
To convert cm³ to L(liter), we utilize the advent of a unit fraction that comprises a liter in the upper part of the fraction(numerator) and a cubic centimeter in the lower part of the fraction(denominator)
Recall that:
1000 cm³ = 1 liter
∴
238.0 cm³ = 
= 0.238 L
Answer:
0.08moles
Explanation:
Given parameters:
Volume of gas = 0.5L
Pressure of gas = 400kPa
Temperature of gas = 300K
Unknown:
Number of moles of N₂ = ?
Solution:
Applying the ideal gas law which is a combination of the three gas law: Boyle's law, Charles's law and Avogadro's law will solve this problem.
The ideal gas law is stated as;
PV = nRT
P is the pressure of the gas
V is the volume of the gas
n is the number of moles
R is the gas constant
T is the temperature of the gas
We need to convert kPa of the pressure to atm which is a more comfortable unit to work with.
400kPa will be
= 3.95atm
Input the variables in the equation;
3.95 x 0.5 = n x 0.082 x 300
n = 0.08moles