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GarryVolchara [31]
3 years ago
9

M=40g V=31cm^3 what is the density

Chemistry
1 answer:
zepelin [54]3 years ago
4 0
40g/31cm^3=1.3g/cm^3
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an electron in the 3rd shell of an Aluminium atom moves to the first shell in a bombardment process. Calculate the frequency of
Liula [17]

Following the quantic theory, the energy of a photon equals the radiation frequency multiplied by the universal constant. ν = 2.923x10¹⁵ Hz. E = 3.09x10¹⁵Hz.

<h3>What is quantum mechanic?</h3>

It is the branch of physics that studies objects and forces at a very low scale, at atoms, subatoms, and particles levels.

Quantum mechanics states that the elemental particles that constitute matter -electrons, neutrons, protons- have the properties of a wave and a particle.

It emerges from the quantic theory exposed by Max Planck (1922), in which he affirmed that light propagates in energy packages or photons.

He discovered the Universal Planck constant, h, used to calculate the energy of a photon.

He stated that the energy of a photon (E) equals the radiation frequency (ν) multiplied by the universal constant (h).

E = νh

In the exposed example, we need to calculate the energy required to change from the 3rd shell to the first shell.

To do it, we should know that the energy in a level (Eₙ) equals the energy associated to an electron in the most inferior energy level (E₁) divided by the square of the shell number (n²).

Eₙ = E₁ / n²

E₁ is a constant. We can express it in <em>Joules </em>or <em>electroVolts </em>

  • E₁ = -2.18x10⁻¹⁸ J
  • E₁ = -13.6 eV

So, let us calculate the energy at level 1 and 3

Eₙ = E₁ / n²

  • E₁ =  -2.18x10⁻¹⁸ J / 1² =<u>  -2.18x10⁻¹⁸</u><u> J</u>

        E₁ =  -13.6 eV / 1² =<u>  -13.6 </u><u>eV</u>

  • E₃ =  -2.18x10⁻¹⁸ J / 3² =  -2.18x10⁻¹⁸ J / 9 =<u> - 2.42x10⁻¹⁹ </u><u>J</u>

        E₃ =  -13.6 eV / 3² =  -13.6 eV / 9 = <u>- 1.51 </u><u>eV</u>

The change of energy can be calculated in two ways,

<u>Option 1</u>

ΔE = E₁ - E₃ = 2.18x10⁻¹⁸ - 2.42x10⁻¹⁹ =<u> 1.93x10⁻¹⁸</u><u>J</u>

ΔE = E₁ - E₃ = 13.6 - 1.51 = <u>12.09 </u><u>eV</u>

<u>Option 2</u>

ΔE = -2.18x10⁻¹⁸ J (1/nf² - 1/ni²)

ΔE =-13.6 eV (1/nf² - 1/ni²)

Where nf is the final level and ni is the initial level. When the electron passes from its initial level to its final level it is called electronic transition.

  • ni = 3
  • nf = 1

ΔE = -2.18x10⁻¹⁸ J (1/nf² - 1/ni²)

ΔE = -2.18x10⁻¹⁸ J (1/1² - 1/3²)

ΔE = -2.18x10⁻¹⁸ J (1 - 0.111)

ΔE = -2.18x10⁻¹⁸ J (0.888)

<u>ΔE</u><u> = - 1.937x10⁻¹⁸ </u><u>J</u>

or

ΔE = -13.6 eV  (1/nf² - 1/ni²)

ΔE = -13.6 eV  (1/1² - 1/3²)

ΔE = -13.6 eV  (1 - 0.111)

ΔE = -13.6 eV  (0.888)

<u>ΔE</u><u> = -12.08</u><u> eV</u>

This is the energy required for the electron to go from n= 3 to n = 1. The negative sign (-) means energy (as light or photons) released or emitted.

<u />

If we want to express the result in Hz, we just need to make a conversion.

1Hz ⇔ 6.626x10⁻³⁴J ⇔ 4.136x10¹⁵ eV.

The energy required for the electron to go from n= 3 to n = 1 is <u>3.09x10¹⁵ </u><u>Hz</u><u>.</u>

Now, we need to calculate the frequency, ν. This is, how many times the wave oscillates back and foward per second.

To do it, we will use the universal Planck constant, h, and the absolute value of the energy, E.

ν = E/h = 1.937x10⁻¹⁸ J / 6.626x10⁻³⁴ Js = 2.923x10¹⁵ 1/s =  <u>2.923x10¹⁵ Hz</u>.

<u>Answer</u>:

  • Frequency, ν = E/h = <u>2.923x10¹⁵ </u><u>Hz</u>.
  • Energy, E = <u>3.09x10¹⁵ </u><u>Hz</u><u>.</u>

You can learn more about quantum mechanic at

brainly.com/question/11855107

brainly.com/question/23780112

brainly.com/question/11852353

5 0
2 years ago
Which statement is correct?
rosijanka [135]

Answer:

B. Chemical changes produce new substances; physical changes do not.

Explanation:

Physical changes only alter appearances, while chemical changes are interactions that create new chemical formulas.

4 0
3 years ago
Cool air can hold less water vapor than warm air. Apply this fact to explain why clouds and precipitation form on the windward s
Simora [160]

The pressure is directly proportional to temperature (when the pressure decrease the temperature decrease too). Because the air parcel expands so the molecules will not interact with each other as much.

The energy of the particles does not change but the fact that the particles are more spaced out means the parcel is cooler.

so now, the warmer a parcel of air the more water vapor it can hold. so, if a parcel of air cools it's ability to hold water vapor drops and if it drops to a low enough point that is when the water vapor will condense and turn back into liquid water. This is how clouds and precipitation form on the the windward side of the mountain.

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3 years ago
A Gold ring is a what?<br> Element<br> Compound<br> Colloid<br> Alloy
Korvikt [17]

Answer: Alloy

Explanation: gold is an alloy, or mixture of metals

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What is the specific heat capacity of propan-1-ol​
Aliun [14]

Answer:

11–350°

Explanation:

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