Why is boiling point for carbon tertrachloride igher than methanol?
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3.08 is the pOH of a 0.175 M aqueous solution of .
0.215% is the per cent ionization of a 0.325 M aqueous solution of
pH is a measure of how acidic/basic water is.
A)
→
Kb = 4.5 x
Kb = {concentration of (NH₄⁺) x concentration of (OH⁻)} ÷ concentration of (NH₃).
concentration of (NH₄⁺) = concentration of (OH⁻) = x.
x² = Kb x concentration of (NH₃)
x² = 4.5 × 10⁻⁶ × 0.175 = 7.0 × 10⁻⁷.
x = concentration of (OH⁻) = √(7.0 × 10⁻⁷)
= 8.367 × 10⁻⁴
pOH = -log(c(OH⁻))
=- log ( 8.367 × 10⁻⁴)
= 3.08
B)
Chemical reaction: NX₃ + H₂O ⇄ NX₃H⁺ + OH⁻.
Concentration of (NX₃) = 0.325 M.
Kb = 4.5 x 10⁻⁶.
[NX₃H⁺] = [OH⁻] = x.
[NX₃] = 0.325 M - x.
Kb = [NX₃H⁺] x [OH⁻] ÷ [NX₃].
4.5 x 10⁻⁶ = x² ÷ (0.325 M - x).
x = 0.0007 M.
Per cent of ionization:
α = 0. 0007 M ÷ 0. 325 M x 100%
= 0.215%.
Hence,
3.08 is the pOH of a 0.175 M aqueous solution of .
0.215% is the per cent ionization of a 0.325 M aqueous solution of
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<h3>Answer:</h3>
Longest wavelength = 343.7 nm
<h3>Solution and Explanation:</h3>In this question we need to first use the concept of energy of a photon.
Energy of a photon, E, is given by the formula, E = hf, where h is the plank's constant, f is the frequency.
But since, f is given by dividing speed, c, by wavelength, λ, then;
E = hc/λ
We are given 348 kJ/mol required to break carbon-carbon bonds.
We know that; 1 mole of bonds = 6.022 × 10^23 bonds.
We are required to find the longest wavelength with enough energy to break the C-C bonds.
This can be worked out in simple steps:
Step 1: Energy required to break one bond (kJ/bond)
1 mole of bonds = 6.022 × 10^23 bonds.
Therefore;
348 kJ = 6.022 × 10^23 bonds.
Thus;
1 bond = 348 kJ ÷ 6.022 × 10^23 bonds.
= 5.778 x 10^-22 kJ
But; 1000 joules = 1 kJ
Hence; energy per bond = 5.778 x 10^-19 Joules
Step 2: Energy per photon
Breaking one bond requires energy equivalent to energy of a photon.
Therefore;
1 photon = 5.778 x 10^-19 Joules
= 5.778 x 10^-19 J/photon
Step 3: Calculating the wavelength
From the equation of energy of a photon;
E = hc/λ
h is the plank's constant = 6.626 × 10^-34 J/s
c is the speed of light in vacuum = 2.9998 × 10^8 m/s
E is the energy of a photon = 5.778 x 10^-19 Joules
Therefore, making λ (wavelength) the subject;
= 3.437 x 10^-7 m
But; 1 nm = 10^-9 m
Thus;
wavelength = 343.7 nm
Therefore, the longest wavelength of the radiation will be 343.7 nm