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kirill115 [55]
4 years ago
15

The 488 nm laser is shine on a lithium metal whose work function is 2.9 eV will you be able to see any photoelectrons? if yes wh

at is the kinetic energy of the electrons if no what wavelength of light should be used to see the photoelectrons
Chemistry
1 answer:
nalin [4]4 years ago
3 0

Answer:

There will not be any ejection of photoelectrons

Explanation:

Energy of the photon= hc/λ

Where;

h= Plank's constant

c= speed of light

λ= wavelength of the incident photon

E= 6.6×10^-34 × 3 ×10^8/488 × 10^-9

E= 4.1 ×10^-19 J

Work function of the metal (Wo)= 2.9 eV × 1.6 × 10^-19 = 4.64 × 10^-19 J

There can only be ejected photoelectrons when E>Wo but in this case, E<Wo hence there will not be any ejection of photoelectrons.

You might be interested in
Give an example of how each compound is used or found in nature. Be sure to use complete sentences.
puteri [66]
Water is found in lakes and rivers. Its purpose in nature is to hydrate animals

Hydrogen gas is not abundant in nature, but hydrogen is abundant in water. Hydrogen (bonds) help ice float. Otherwise, freezing lakes would kill animals (it actually doesn't since the ice creates a "coat" above the water").

Ammonia is nitrogen-rich molecules that plant uses to get their nitrogen. It comes from the part of the nitrogen cycle where dead plants and animals are decayed.

Carbon dioxide is what we exhale. Plants "inhale" carbon dioxide and use that for photosynthesis.

Hydrogen sulfide is emitted by volcanoes and by anaerobic (oxygen-less) decay from bacteria.

Have an awesome day! I hope this helps.
8 0
3 years ago
At a given temperature, 2.6 atm of h2 and 3.14 atm of cl2 are mixed and allowed to come to equilibrium. the equilibrium pressure
Keith_Richards [23]

The solution would be like this for this specific problem:

<span>Given:

H2 = </span><span>2.6 atm
CL2 = 3.14 atm</span>

 

<span>
pressure H2 = 2.6 - x 
pressure Cl2 = 3.14 - x 
<span>pressure HBr = 2x = 1.13

x = 1.13 / 2 = 0.565 

<span>pressure H2 = 2.6 - 0.565 = 2.035
pressure Br2 = 3.14 - 0.565 = 2.575 

Kp = (1.13)^2 / 2.035 x 2.575</span></span></span>

 

= 1.2769 / (5.240125)

= 0.24367739319195629875241525726963

= 0.244

<span>Therefore, the Kp for the reaction at the given temperature is 0.244.

To add, </span>the hypothetical pressure of a gas if it alone occupied the whole volume of the original mixture at the same temperature is called the partial pressure or Kp.

7 0
3 years ago
a 25 ml volume of a sodium hydroxide solution requires 19.6 mL of a 0.189 M HCl acid for neutralization. A 10 mL volume of phosp
Drupady [299]

Answer: 0.172 M

Explanation:

a) To calculate theconcentration of base, we use the equation given by neutralization reaction:

n_1M_1V_1=n_2M_2V_2

where,

n_1,M_1\text{ and }V_1 are the n-factor, molarity and volume of acid which is HCl

n_2,M_2\text{ and }V_2 are the n-factor, molarity and volume of base which is NaOH.

We are given:

n_1=1\\M_1=0.189M\\V_1=19.6mL\\n_2=1\\M_2=?\\V_2=25mL

Putting values in above equation, we get:

1\times 0.189\times 19.6=1\times M_2\times 25\\\\M_2=0.148

b) To calculate the concentration of acid, we use the equation given by neutralization reaction:

n_1M_1V_1=n_2M_2V_2

where,

n_1,M_1\text{ and }V_1 are the n-factor, molarity and volume of acid which is H_3PO_4

n_2,M_2\text{ and }V_2 are the n-factor, molarity and volume of base which is NaOH.

We are given:

n_1=3\\M_1=?\\V_1=10mL\\n_2=1\\M_2=0.148\\V_2=34.9mL

Putting values in above equation, we get:

3\times M_1\times 10=1\times 0.148\times 34.9\\\\M_1=0.172M

The concentration of the phosphoric acid solution is 1.172 M

3 0
3 years ago
Which of the following isotopes is NOT considered to be a major threat to human health from nuclear fallout? a. strontium-90 b.
Nat2105 [25]
Ohhh it’s A) strontium
4 0
3 years ago
Select all of the following equations that represent an exothermic reaction.
masya89 [10]

Answer:

C(graphite) → C(diamond), ΔH = - 0.45 kcal

CH4 + 2O2 → CO2 + 2H2O + 212,800 cal

Explanation:

C(graphite) → C(diamond), ΔH = - 0.45 kcal

CH4 + 2O2 → CO2 + 2H2O + 212,800 cal

These reactions are exothermic reaction because heat is evolved.

The energy changes occur during the bonds formation and bonds breaking.

There are two types of reaction endothermic and exothermic reaction.

Endothermic reactions:

The type of reactions in which energy is absorbed are called endothermic reactions.

In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.

For example:

C + H₂O   →  CO  + H₂

ΔH = +131 kj/mol

it can be written as,

C +  H₂O  + 131 kj/mol  →  CO  + H₂

Exothermic reaction:

The type of reactions in which energy is released are called exothermic reactions.

In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.

For example:

Chemical equation:

C + O₂   →  CO₂

ΔH = -393 Kj/mol

it can be written as,

C + O₂   →  CO₂ + 393 Kj/mol

6 0
3 years ago
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