Chapter 21: Problem 74
A \(100 \mathrm{~W}\) lamp has a steady current of \(0.83 \mathrm{~A}\) in its filament. How long is required for 1 mol of electrons to pass through the lamp?
Short Answer
Expert verified
It takes approximately 116235 seconds for 1 mole of electrons to pass through the lamp.
Step by step solution
01
Understand the Problem
We need to find out how long it takes for 1 mole of electrons to pass through a lamp with a steady current of 0.83 A.
02
Use the Formula for Current
Current is defined as the flow of charge per time. The formula for current is given by the equation: \[ I = \frac{Q}{t} \]where \(I\) is the current, \(Q\) is the electric charge, and \(t\) is the time. We need to solve for \(t\), so we rearrange the equation as \[ t = \frac{Q}{I} \].
03
Calculate the Charge for 1 Mole of Electrons
1 mole of electrons contains Avogadro's number of electrons, which is approximately \(6.022 \times 10^{23}\) electrons. The charge of one electron is approximately \(1.602 \times 10^{-19}\) coulombs. Therefore, the total charge \(Q\) of 1 mole of electrons is: \[ Q = 6.022 \times 10^{23} \times 1.602 \times 10^{-19} \]\[ Q \approx 96485 \text{ C} \]This value is also known as the Faraday constant.
04
Calculate the Time
Now that we have the charge, we can substitute \(Q\) into the rearranged current formula:\[ t = \frac{96485 \text{ C}}{0.83 \text{ A}} \]Calculating this gives:\[ t \approx 116235 \text{ seconds} \].
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!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Electric Charge
Electric charge is a fundamental property of matter. It's like a small packet of energy that particles carry. When we talk about electric charge, we often refer to two types: positive and negative. These charges create electric fields and currents, impacting how particles interact with each other.
- Electrons have a negative charge of approximately \( -1.602 \times 10^{-19} \) coulombs.
- Protons, on the other hand, have a positive charge of the same magnitude.
Avogadro's Number
Avogadro's number is a huge number that helps us count particles, like atoms and molecules, in chemistry. This number is approximately \( 6.022 \times 10^{23} \), representing how many atoms, ions, or molecules are in one mole of a substance.
- Used widely in both chemistry and physics.
- Helps connect the macroscopic world with the microscopic world.
Faraday Constant
The Faraday constant is a physical constant that represents the charge of one mole of electrons. It's approximately equal to \( 96485 \) coulombs per mole.
- This value stems from multiplying Avogadro's number by the charge of a single electron.
- It's widely used in electrochemistry when calculating electric charge.
Time Calculation
Time calculation in the context of electric circuits involves understanding how long it takes for a certain amount of charge to pass through a conductor. To calculate this, we often use the formula: \[ I = \frac{Q}{t} \]Where:
- \( I \) is the current in amperes.
- \( Q \) is the charge in coulombs.
- \( t \) is the time in seconds.