Ch.7 - Quantum MechanicsWorksheetSee all chapters
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Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: In order to comply with the requirement that energy be conserved, Einstein showed in the photoelectric effect that the energy of a photon (hν) absorbed by a metal is the sum of the work function (ϕ), which is the minimum energy needed to dislodge an electron from the metal’s surface, and the kinetic energy (Ek) of the electron: hν = ϕ + E k. When light of wavelength 358.1 nm falls on the surface of potassium metal, the speed (u) of the dislodged electron is 6.40 x 105 m/s. What is ϕ (in J) of potassium?

Solution: In order to comply with the requirement that energy be conserved, Einstein showed in the photoelectric effect that the energy of a photon (hν) absorbed by a metal is the sum of the work function (ϕ),

Problem

In order to comply with the requirement that energy be conserved, Einstein showed in the photoelectric effect that the energy of a photon (hν) absorbed by a metal is the sum of the work function (ϕ), which is the minimum energy needed to dislodge an electron from the metal’s surface, and the kinetic energy (Ek) of the electron: hν = ϕ + E k. When light of wavelength 358.1 nm falls on the surface of potassium metal, the speed (u) of the dislodged electron is 6.40 x 105 m/s. What is ϕ (in J) of potassium?

Solution

The mathematical representation of the photoelectric effect is:

Since the energy of a photon (Ephoton) is also equal to (h∙v) where h is Planck’s constant (6.626x10-34 J∙s) and v is the frequency (in Hz or s-1), and work function can be denoted as ϕ, the photoelectric equation can be written as:

Therefore, the equation for work function, ϕ is:


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