The work function of palladium (Pd) is 5.22 eV. What is the minimum frequency of light to observe the photoelectric effect from
a Pd surface? If light with a 200 nm wavelength is absorbed by the Pd surface, what is the velocity of the emitted electrons?
1 answer:
Answer:
1)4×10^13Hz
2) 9.95×10-9J
Explanation:
From the image attached, it is clear that the work function of the palladium metal must first be obtained in joules. Then, the frequency is obtained from E=hf.
The kinetic energy if the photoelectrons is obtained as the difference between the energy of the photon and the work function of the metal.
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Taking into account the definition of Avogadro's number and molar mass, 3.49334×10²² molecules of sucrose are present.
<h3>Definition of molar mass</h3>The molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.
<h3>Avogadro's Number</h3>Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.
<h3>Molecules of sugar in this case</h3>In first place, the molar mass of sucrose is 342 g/mole. So, you can apply the following rule of three: If by definition of molar mass 342 grams of the compound are contained in 1 mole, 20 grams of the compound are contained in how many moles?
<u><em>amount of moles= 0.058 moles</em></u>
Now, considering the Avogadro's number, you can apply the following rule of three: If 1 mole of the compound contains 6.023×10²³ molecules, 0.058 moles contains how many molecules?
amount of moleculas= (6.023×10²³ molecules × 0.058 moles)÷ 1 mole
<u><em>amount of molecules= 3.49334×10²² molecules</em></u>
Finally, 3.49334×10²² molecules of sucrose are present.
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molar mass:
Avogadro's Number:
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Answer: 26.5 mm Hg
Explanation:
The vapor pressure is determined by Clausius Clapeyron equation:
where,
= initial pressure at
= ?
= final pressure at
= 100 mm Hg
= enthalpy of vaporisation = 28.0 kJ/mol =28000 J/mol
R = gas constant = 8.314 J/mole.K
= initial temperature =
= final temperature =
Now put all the given values in this formula, we get
Thus the vapor pressure of in mmHg at 26.5 ∘C is 26.5