Answer:
C
Explanation:
The Henderson-Hasselbalch equation relates pH to the concentrations of an weak acid-base conjugate pair as follows:
pH = pKa + log([A⁻]/[HA])
For solution 1, the pH may be expressed as follows:
pH = pKa + log(5.0M/5.0M) = pKa
For solution 2, pH may be expressed as follows:
pH = pKa + log(0.050M/0.050M) = pKa
Thus, the pH values are equal to the pKa in both cases and are the same.
Answer:
When [F⁻] exceeds 0.0109M concentration, BaF₂ will precipitate
Explanation:
Ksp of BaF₂ is:
BaF₂(s) ⇄ Ba²⁺(aq) + 2F⁻(aq)
Ksp = 1.7x10⁻⁶ = [Ba²⁺] [F⁻]²
The solution will produce BaF₂(s) -precipitate- just when [Ba²⁺] [F⁻]² > 1.7x10⁻⁶.
As the concentration of [Ba²⁺] is 0.0144M, the product [Ba²⁺] [F⁻]² will be equal to ksp just when:
1.7x10⁻⁶ = [Ba²⁺] [F⁻]²
1.7x10⁻⁶ = [0.0144M] [F⁻]²
1.18x10⁻⁴ = [F⁻]²
0.0109M = [F⁻]
That means, when [F⁻] exceeds 0.0109M concentration, BaF₂ will precipitate
Answer:
1.35 moles of O²⁻
21.6 grams of O²⁻
Explanation:
We know that the charge on Aluminium ion is +3 (i.e. Al³⁺) while, the charge on Oxide ion is -2 (i.e. O²⁻). Therefore, the overall neutral Al₂O₃ compound has 2 Al³⁺ ions and 3 O²⁻ ions. Since, we can say that,
1 mole of Al₂O3 contains = 3 moles of O²⁻ ions
So,
0.450 moles of Al₂O₃ will have = X g of O²⁻
Solving for X,
X = 0.450 mol × 3 mol ÷ 1 mol
X = 1.35 moles of O²⁻
As the mass of an atom is mainly due to the presence of protons and neutrons hence, the addition of two electrons (-ve 2 shows two gained electron) to Oxygen will make a negligible change to the atomic masss of Oxygen because electron is said to be almost 1800 times lighter than proton. Hence, the ionic mass of O²⁻ will be 16 g/mol and the mass of given moles is calculated as,
Mass = Moles × Ionic Mass
Mass = 1.35 mol × 16 g/mol
Mass = 21.6 g
Greenhouse effect is the natural phenomenon which makes the Earth's atmosphere favorable for any form of life. As the sun's rays radiates into the atmosphere, some are deflected while some are absorbed. The Earth reflects this back, causing the heat to be trapped. At night, this keeps the Earth warm enough. Without the greenhouse effect, nights would be too cold and days would be too hot that life cannot be sustained.
