Skip to main content
Ch.8 - The Quantum-Mechanical Model of the Atom
Tro - Chemistry: A Molecular Approach 6th Edition
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217Not the one you use?Change textbook
All textbooksTro 6th EditionCh.8 - The Quantum-Mechanical Model of the AtomProblem 58
Chapter 8, Problem 58

An electron traveling at 3.7×105 m/s has an uncertainty in its velocity of 1.88×105 m/s. What is the uncertainty in its position?

Verified step by step guidance
1
Identify the relevant principle: This problem involves the Heisenberg Uncertainty Principle, which relates the uncertainty in position (\( \Delta x \)) and the uncertainty in momentum (\( \Delta p \)).
Recall the Heisenberg Uncertainty Principle formula: \( \Delta x \cdot \Delta p \geq \frac{h}{4\pi} \), where \( h \) is Planck's constant (\( 6.626 \times 10^{-34} \text{ Js} \)).
Determine the uncertainty in momentum (\( \Delta p \)): Since momentum \( p = m \cdot v \), the uncertainty in momentum \( \Delta p = m \cdot \Delta v \), where \( m \) is the mass of the electron (\( 9.11 \times 10^{-31} \text{ kg} \)) and \( \Delta v \) is the uncertainty in velocity.
Substitute the known values into the formula for \( \Delta p \): \( \Delta p = 9.11 \times 10^{-31} \text{ kg} \times 1.88 \times 10^{5} \text{ m/s} \).
Use the Heisenberg Uncertainty Principle to solve for \( \Delta x \): Rearrange the formula to \( \Delta x \geq \frac{h}{4\pi \cdot \Delta p} \) and substitute the calculated \( \Delta p \) and known \( h \) to find \( \Delta x \).

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
6m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Heisenberg Uncertainty Principle

The Heisenberg Uncertainty Principle states that it is impossible to simultaneously know both the exact position and exact momentum (or velocity) of a particle. This principle highlights a fundamental limit to measurement in quantum mechanics, indicating that the more precisely one property is measured, the less precisely the other can be controlled or known.
Recommended video:
Guided course
01:09
Heisenberg Uncertainty Principle

Momentum

Momentum is a physical quantity defined as the product of an object's mass and its velocity. In the context of quantum mechanics, momentum is often represented as a vector quantity, and its uncertainty is directly related to the uncertainty in the particle's position, as described by the Heisenberg Uncertainty Principle.
Recommended video:
Guided course
00:40
Angular Momentum Quantum Number

Calculating Uncertainty

To calculate the uncertainty in position (Δx) when given the uncertainty in velocity (Δv), one can use the formula Δx * Δp ≥ ħ/2, where Δp is the uncertainty in momentum and ħ is the reduced Planck's constant. Since momentum (p) is mass (m) times velocity (v), the uncertainty in momentum can be expressed as Δp = m * Δv, allowing for the determination of Δx when Δv is known.
Recommended video:
Guided course
02:05
Uncertainty Principle Formula
Related Practice
Textbook Question

Calculate the de Broglie wavelength of a 143-g baseball traveling at 85 mph. Is the wave nature of matter significant for a baseball?

Textbook Question

A 0.22-caliber handgun fires a 1.9-g bullet at a velocity of 745 m/s. Calculate the de Broglie wavelength of the bullet. Is the wave nature of matter significant for bullets?

Textbook Question

What are the possible values of l for each given value of n? a. 1 b. 2 c. 3 d. 4

Textbook Question

Which electron is, on average, farther from the nucleus: an electron in a 3p orbital or an electron in a 4p orbital?

2
views
Textbook Question

An electron has an uncertainty in its position of 552 pm. What is the uncertainty in its velocity?

1
views