Answer:
atomic number- 42
chemical number- 96
number of protons-18
atomic mass-96
number of eletrons-42
number of valence eletrons- 1, 2, 13, or 18. (sorry i forgot)
nummber of shells in n=3 shell-18
number of neutrons-54
Explanation:
well i just know the periodic table by heart and thats how i got the answer XD
Answer:
3.51
Explanation:
Before any sodium hydroxide has been added, the pH is that of the aqueous hydrofluoric acid solution.
HF is a weak acid that dissociates according to the following equation.
HF(aq) ⇄ H⁺(aq) + F⁻(aq) Ka = 6.76 × 10⁻⁴
We can find [H⁺] using the following expression.
[H⁺] = √(Ca × Ka)
where
Ca: concentration of the acid
Ka: acid dissociation constant
[H⁺] = √(Ca × Ka)
[H⁺] = √(0.458 × 6.76 × 10⁻⁴)
[H⁺] = 3.10 × 10⁻⁴ M
The pH is:
pH = -log [H⁺]
pH = -log 3.10 × 10⁻⁴ = 3.51
