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snow_lady [41]
3 years ago
8

Please help(15 points)

Chemistry
2 answers:
Triss [41]3 years ago
4 0

Answer: because they take a lot of tie to form  

Lapatulllka [165]3 years ago
3 0
Because they take a lot time to form
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What is the kinetic energy of the emitted electrons when cesium is exposed to UV rays of frequency 1.0×1015Hz?
RideAnS [48]

The kinetic energy of the emitted electrons of cesium when it is exposed to UV rays of frequency 1.0 \times {10^{15}}\;{\text{Hz}}  is  \boxed{6.63 \times {{10}^{ - 19}}\;{\text{J}}}

Further Explanation:

Photoelectric effect:

When light is made to fall on any substance, electrons are emitted from it. This is known as the photoelectric effect and the emitted electrons are called photoelectrons. The electrons are emitted because of the transference of energy from light to the electrons.

Cesium is a member of the alkali metal group so it is highly reactive and shows photoelectric effect to the maximum extent. It can remove its electron so easily because of its atomic size. Due to large atomic size of cesium, its outermost electrons are held very less tightly to the nucleus and therefore removed easily.

According to the Planck-Einstein equation, the energy is proportional to the frequency and is expressed as follows:

{\mathbf{E=h\nu }}                                   ......(1)

Here,

{\text{E}} is the energy.

h is the Plank’s constant.

\nu is the frequency.

The frequency of UV rays is 1.0 \times {10^{15}}\;{\text{Hz}} or 1.0 \times {10^{15}}\;{{\text{s}}^{ - 1}}

The value of Planck’s constant is 6.626 \times {10^{ - 34}}\;{\text{J}}\cdot{\text{s}} .

Substitute these values in equation (1)

\begin{aligned}{\text{E}}&=\left( {6.626 \times {{10}^{ - 34}}\;{\text{J}}\cdot{\text{s}}}\right)\left( {1.0 \times {{10}^{15}}\;{{\text{s}}^{ - 1}}}\right)\\&=6.63\times {10^{ - 19}}\;{\text{J}}\\\end{aligned}

But when electrons are ejected out from the surface of the substance, all of its energy is considered as kinetic energy.

So the kinetic energy of the electrons is {\mathbf{6}}{\mathbf{.63 \times 1}}{{\mathbf{0}}^{{\mathbf{ - 19}}}}\;{\mathbf{J}} .

Learn more:

1. Statement about subatomic particle: brainly.com/question/3176193

2. The energy of a photon in light: brainly.com/question/7590814

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Structure of the atom

Keywords: kinetic energy, frequency, energy, photoelectric effect, Planck's constant, light, electrons, photoelectrons, proportional, transference, reactive, cesium.

7 0
3 years ago
Read 2 more answers
The chemical equation of magnesium and nitric acid
marshall27 [118]
Mg + 2H(NO)3 ⇒ Mg(NO3)2 + H2
5 0
3 years ago
Is O2 always a double bond?
Dima020 [189]
  • O-O single bonds and H-O single bonds in \text{H}_2\text{O}_2 molecules.
  • H-O single bonds in \text{H}_2\text{O} molecules.
  • O=O double bonds in \text{O}_2 molecules.
<h3>Explanation</h3>

How many valence electrons do atoms in each molecule need for them to be stable?

  • Each H atom needs two valence electrons to be stable.
  • Each atom of an element other than H needs eight valence electron to be stable.
  • There are two H atoms and two O atoms in an  \text{H}_2\text{O}_2 molecule. Atoms in each \text{H}_2\text{O}_2 need 2 \times 1 + 2\times 2 = 6 more electrons to be stable.
  • There are two H atoms and one O atom in an \text{H}_2\text{O} molecule. Atoms in each \text{H}_2\text{O} molecule need 2 \times 1 + 2= 4 more electrons to be stable.
  • There are two O atoms in an \text{O}_2 molecule. Atoms in each \text{O}_2 molecule need 2 \times 2 = 4 more electrons to be stable.

How many chemical bonds in each molecule?

Each chemical bond adds one valence electron to each bonding atom. Each chemical bond connects two atoms. As a result, each chemical bond adds two valence electrons to the molecule.

  • Each \text{H}_2\text{O}_2 molecule needs 6 / 2 = 3 chemical bonds.
  • Each \text{H}_2\text{O} molecule needs 4 / 2 = 2 chemical bonds.
  • Each \text{O}_2 molecule needs 4 /2= 2 chemical bonds.

What chemical bonds are these? Again, each H atom needs only one more valence electron to be stable. It will share only one electron with O and form one H-O bond. The rest of the chemical bonds are between O atoms.

  • There are two H atoms in each \text{H}_2\text{O}_2 molecule, which form two H-O bonds. Two of the three chemical bonds in this molecule are H-O. The other is an O-O single bond between the two O atoms.
  • There are two H atoms in each \text{H}_2\text{O} molecule, which form two H-O bonds. Both chemical bonds in this molecule are H-O. There's no O-O bond in this molecule.
  • There is no H atom in \text{O}_2 molecules. Both chemical bonds are between O atoms. However, there are only two O atoms. There must be two chemical bonds between the two O atoms. That bond will be an O-O double bond.
3 0
3 years ago
Read 2 more answers
2. A 2.5 mol SAMPLE OF OXYGEN GAS (O2) INCREASES TO 3.2 mol
lana [24]

696.32 mmHg is the final pressure of the gas.

<h3>What is an ideal gas equation?</h3>

The ideal gas equation, pV = nRT, is an equation used to calculate either the pressure, volume, temperature or number of moles of a gas.

Given data:

P_1 = 720 mmHg              

P_2 = ?

n_1 = 2.5 mol                

n_2 = 3.2 mol

V_1 = 34 L            

V_2 = 45 L

Formula

Combined gas law

\frac{P_1 V_1}{n_1}  = \frac{P_2 V_2}{n_2}

P_2 = 696.32 mmHg

Hence, 696.32 mmHg is the final pressure of the gas.

Learn more about an ideal gas equation here:

brainly.com/question/19251972

#SPJ1

6 0
2 years ago
For each pair, which has higher potential energy?
Allushta [10]

Answer:

Maybe A)

Explanation:

Can you make me the Brainliest answer ?

7 0
3 years ago
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