/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q27P A hot bar of iron glows a dull r... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

A hot bar of iron glows a dull red. Using our simple ball-spring model of a solid (Figure 8.23), answer the following questions,explaining in detail the processes involved. You will need to make some rough estimates of atomic properties based on prior work. (a) What is the approximate energy of the lowest-energy spectral emission line? Give a numerical value. (b) What is the approximate energy of the highest-energy spectral emission line? Give a numerical value. (c) What is the quantum number of the highest-energy occupied state? (d) Predict the energies of two other lines in the emission spectrum of the glowing iron bar. (Note: Our simple model is too simple-the actual spectrum is more complicated. However, this simple analysis gets at some important aspects of the phenomenon.)

Short Answer

Expert verified

(a) The approximate energy of the lowest-energy spectral emission line is2.5×10−20 J .

(b) The approximate energy of the highest-energy spectral emission line is 2.88×10−19 J.

(c) The quantum number of the highest energy occupied state is about 12.

(d) The energies of two other lines in the emission spectrum are5×10−20 J and7.5×10−20 J respectively.

Step by step solution

01

Significance of the energy

The energy is referred to as a qualitative property which is transferred from one object to another object. It can also not be destroyed nor created.

02

(a) Determination of the approximate energy of the lowest energy line

The lowest energy emission spectrum line mainly represents the jump from one to another vibrational energy. The energy required for melting the iron is the energy of the lowest energy emission spectrum line.

The equation of the lowest energy emission spectrum line is expressed as:

E=kT

Here,E is the lowest energy emission spectrum line,k is the Boltzmann constant andT is the iron’s melting point.

Substitute 1.38×10−23J/Kfork and1811‿é forT in the above equation.

E=(1.38×10−23J/K)(1811‿é)=2.5×10−20 J

Thus, the approximate energy of the lowest-energy spectral emission line is 2.5×10−20 J.

03

(b) Determination of the approximate energy of the highest energy line 

The red colour line from the diagram given in the question is the highest energy emission spectral line.

The equation of the energy of the highest emission spectral line is expressed as:

E1=hf

Here,E1 is the energy of the highest emission spectral line,h is the Planck’s constant andf is the red light’s frequency.

Substitute6.626×10−34​J⋅s forh and 435×10−12 s-1forf in the above equation.

E1=(6.626×10−34​J⋅s)(435×10−12 s-1)=2.88×10−19 J

Thus, the approximate energy of the highest-energy spectral emission line is 2.88×10−19 J.

04

(c) Determination of the quantum number 

The equation of the quantum number is expressed as:

N=E1E

Here,N is the quantum number.

Substitute the values in the above equation.

N=2.88×10−19 J2.5×10−20 J=11.52≈12

Thus, the quantum number of the highest energy occupied state is about 12.

05

(d) Determination of the prediction of energies

The equation of the energy of the first line in the emission spectrum is expressed as:

U1=E+E=2E

Here,U1 is the energy of the first line in the emission spectrum.

Substitute the values in the above equation.

U1=2×2.5×10−20 J=5×10−20 J

The equation of the energy of the second line in the emission spectrum is expressed as:

U2=E+2E=3E

Here,U2 is the energy of the second line in the emission spectrum.

Substitute the values in the above equation.

U2=3×2.5×10−20 J=7.5×10−20 J

Here, these calculations are accurate and also wild.

Thus, the energies of two other lines in the emission spectrum are5×10−20 J and7.5×10−20 J respectively.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

For a certain diatomic molecule, the lowest-energy photon observed in the vibrational spectrum is 0.17eV. What is the energy of a photon emitted in a transition from the 5th excited vibrational energy level to the 2nd excited vibrational energy level, assuming no change in the rotational energy?

Energy graphs: (a) Figure 8.41 shows a graph of potential energy vs. interatomic distance for a particular molecule. What is the direction of the associated force at location A? At location B? At location C? Rank the magnitude of the force at locations A,B and C. (That is, which is greatest , which is smallest, and are any of these equal to each other?) For the energy level shown on the graph, draw a line whose height is the kinetic energy when the system is at location D.

(b) Figure 8.42 shows all of the quantized energies (bound states) for one of these molecules. The energy for each state is given on the graph, in electron volts ( 1 eV=1.6×10−19 J). How much energy is required to break a molecule apart, if it is initially in the ground state? (Note that the final state must be an unbound state; the unbound states are not quantized.)

(c) At high enough temperatures, in a collection of these molecules there will be at all times some molecules in each of these states, and light will be emitted. What are the energies in electron volts of the emitted light?

(d) The "inertial" mass of the molecule is the mass that appears in Newton's second law, and it determines how much acceleration will result from applying a given force. Compare the inertial mass of a molecule in the ground state and the inertial mass of a molecule in an excited state10 eV above the ground state. If there is a difference, briefly explain why and calculate the difference. If there isn't a difference, briefly explain why not.)

How many different photon energies would emerge from a collection of hydrogen atoms that occupy the lowest four energy states (N=1,2,3,4) ? (You need not calculate the energies of each states.

N=1 is the lowest electronic energy state for a hydrogen atom. (a) If a hydrogen atom is in a state N=4, what is K+U for this atom (in eV)? (b) The hydrogen atom makes a transition to state N=2, Now what is K+U in electron volts for this atom? (c) What is energy (in eV) of the photon emitted in the transition from level N=4 to N=2? (d) Which of the arrows in figure 8.40 represents this transition?

The first excited state of a mercury atom is 4.9eV above the ground state. A moving electron collides with a mercury atom and excites the mercury atom to its first excited state. Immediately after the collision the kinetic energy of the electron is 0.3eV. What was the kinetic energy of the electron just before the collision?

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.