If light at 193 nm from an argon–fluoride laser is incident on a gold metal surface, electrons with kinetic energy of 1.80 10–
19 J are produced. What is the work function of gold in kJ/mol? What is the minimum wavelength of light in nm required to produce photoelectrons from gold (zero kinetic energy)?
1 answer:
Answer:work function= 8.2×10-19J
Minimum wavelength of light required= 2.4×10-7m
Explanation:
The wavelength of incident light was given as 193nm. We have to convert this to meters and have 193×10-9m. Then we use it to find the energy of incident photon E. When E is found we now apply Einstein photoelectric equation to obtain the work function Wo since the kinetic energy of photoelectrons is known as 1.8×10-19J.
From this work function. We can obtain the minimum wavelength of light required. All these steps are shown in the image attached.
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1st equation :
2nd Equation:
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k = 0.046
C = concentration at time t
C0 = initial conc.
k = rate constant
t = time
1st equation :
2nd Equation:
Find
k = 0.046
Answer:
The heat absorbed by the water is 228,948.48 J
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
In this way, between heat and temperature there is a direct proportional relationship (Two magnitudes are directly proportional when there is a constant so that when one of the magnitudes increases, the other also decreases; and the same happens when either of the two decreases .). The constant of proportionality depends on the substance that constitutes the body and its mass, and is the product of the specific heat and the mass of the body. So, the equation that allows to calculate heat exchanges is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the variation in temperature.
In this case:
- c= 4.184
- m=855 g
- ΔT= Tfinal - Tinitial= 85 °C - 21°C= 64 °C
Replacing:
Q= 4.184 *855 g* 64 C
Solving:
Q= 228,948.48 J
<u><em>The heat absorbed by the water is 228,948.48 J</em></u>