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3 years ago

How did the quantum mechanical model of the atom improve on Borh's atomic model?

1 answer:

7 0

n the Bohr Model, the electron is treated as a particle in fixed orbits around the nucleus. In the Quantum Mechanical Model, the electron is treated mathematically as a wave. The electron has properties of both particles and waves.

The Bohr model was a one-dimensional model that used one quantum number to describe the distribution of electrons in the atom. The only information that was important was the size of the orbit, which was described by “n” the principle quantum number.

Schrodinger's model (Quantum Mechanical Model) allowed the electron to occupy three-dimensional space. It, therefore, required three coordinates, or three quantum numbers, to describe the distribution of electrons in the atom.

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a 50.00-mL sample of bleach solution contains 0.214 M HClO and 0.667 M NaClO. The Ka of hypochlorous acid is 3.0 ✕ 10−8. Find th

amm1812

Answer:

A) pH = 8.11

B) pH = 7.96

Explanation:

The pH of buffer is calculated using Henderson Hassalbalch's equatio, which is

$pH=pKa+log\frac{[salt]}{[acid]}$

pKa = -logKa = -log(3.0 ✕ 10⁻⁸)

pKa = 7.5

[salt] = 0.667

[Acid] = 0.214

$pH = 7.5 + log\frac{0.667}{0.214}=7.99$

A) If the solution is halved it means the concentration of both salt and acid will be the same.

The volume will change

Number of moles of acid = molarity X volume = 0.214 X 25 = 5.35 mmol

Number of moles of salt = molarity X volume = 0.667 X 25 = 16.68 mmol

moles of NaOH added = molarity X volume = 0.100 X 10 = 1 mmol

These moles of NaOH will react with acid to give same amount of salt and thus the moles of acid will decrease

New moles of acid = 5.35 - 1 = 4.35

New moles of salt = 16.68 + 1 = 17.68

the new pH will be

$pH = 7.5 + log\frac{17.68}{4.35}=8.11$

moles of HCl added = molarity X volume = 0.100 X 10 = 1 mmol

These moles of HCl will react with salt to give same amount of acid and thus the moles of salt will decrease

New moles of acid = 5.35 + 1 = 6.35

New moles of salt = 16.68 - 1 = 15.68

the new pH will be

$pH = 7.5 + log\frac{15.68}{5.35}=7.97$

3 0

3 years ago

How many atoms does 5.06 grams of oxogen have

blagie [28]

Answer: 1.90x10²³ atoms of O

Explanation: First convert the mass of O into moles:

5.06 g O x 1 mole O / 16 g O

= 0.32 moles O

Next use Avogadro's Number to find the number of atoms of O

0.32 moles O x 6.022x10²³ atoms O / 1 mole O

= 1.90x10²³ atoms O

7 0

4 years ago

Which statements correctly describe the effect of distance in determining the gravitational force and the electrical force? Chec

Luda [366]

Answer:

The gravitational force is inversely proportional to the square of the distance..

The electrical force is inversely proportional to the square of the distance..

Explanation:

From the Newton's law of universal gravity, we understood that the force of attraction between the masses two objects is inversely proportional to the square of the distance apart. Mathematically, it is expressed as:

F = GM1M2/r²

Where:

M1 and M2 are the masses of two objects measured in kilograms (Kg).

G is the gravitational constant with a value of 6.67×10¯¹¹ Nm²/Kg²

r is the distance apart measured in metre (m).

F is the force of attraction measured in Newton (N).

From the equation:

F = GM1M2/r²

The force (F) is inversely proportional to the square of the distance (r) apart. This means that the greater the distance apart, the smaller the force of attraction and the smaller the distance apart, the greater the force of attraction between the masses of the object.

From Coulomb's Law, we understood that the force of attraction between two charged particles is inversely proportional to square of the distance. Mathematically, it expreessed as

F = Kq1q2/ r²

Where:

q1 and q2 are charges of two objects measured in coulomb (C) .

r is the distance apart measured in metre (m)

K is the electrostatic constant with a value of 9×10^9 Nm²/C²

F is the force measured in Newton (N).

From the equation:

F = Kq1q2/ r²

The force (F) is inversely proportional to the square of the distance (r) apart.. This implies that as the distance between the charged particles increase, the smaller the force of attraction between them and as the distance between the charged particles decrease, the greater the force of attraction between the two charged particles.

6 0

4 years ago

Which compounds are the Brønsted-Lowry bases on this equilibrium

vovangra [49]

The answer is E.
Hope it helps.

8 0

3 years ago

3 Zn + 2 MnF3 ---------> 2 Mn + 3 ZnF2

cricket20 [7]

Answer:I’ll ask my teacher

Explanation:

8 0

3 years ago