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
The heat required to vaporize 43.9 g of acetone at its boiling point is calculated as below
the heat of vaporization of acetone at its boiling point is 29.1 kj/mole
find the moles of acetone = mass/molar mass
= 43.9g /58 g/mol =0.757 moles
heat (Q) = moles x heat of vaporization
= 29.1 kj/mole x 0.757 moles = 22.03 kj
Answer:
Explanation:
To write the chemical symbol for an atom or cation with 22 electrons, we must understand some few things about an atom.
An atom is made up of positively charged paticles called protons which are located in the nucleus. The neutrons do not have any charges and are they reside together in the nucleus with the protons.
Electrons are negatively charged particles which orbits the nucleus.
Titanium in its neutral state is the 22nd element on the periodic table and it has 22 electrons.
Vanadium is the the 23rd element on the periodic table. If it loses an electron, it becomes positively charged and it is a cation.
Chromium is the 24th element on the periodic table. A loss of two electrons makes the net electrons remaining on it 22.
The symbols are:
₂₂Ti
₂₃V¹⁺
₂₄Cr²⁺
