Ch.2 - Atoms & ElementsWorksheetSee all chapters
All Chapters
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:
An experimental apparatus has an upper chamber into which oil drops are sprayed over a plate with a positive charge. Drops can fall through a hole in the plate to a lower chamber, into which x-rays are beamed above a negatively charged plate. (1) X-ray irradiation causes drops to pick up electrons and become negatively charged. (2) The force of gravity pulls drops downward but is opposed by the electric field that pushes the negatively charged drops upward. A microscopic view shows drops of different sizes moving upward and downward. . Millikan’s oil-drop experiment to measure the charge of the electron. Small drops of oil are allowed to fall between electrically charged plates. Millikan measured how varying the voltage between the plates affected the rate of fall. From these data he calculated the negative charge on the drops. Because the charge on any drop was always some integral multiple of 1.602 10-19C, Millikan deduced this value to be the charge of a single electron.
Are the masses of the oil drops changed significantly when electrons accumulate on them?

Solution: . Millikan’s oil-drop experiment to measure the charge of the electron. Small drops of oil are allowed to fall between electrically charged plates. Millikan measured how varying the voltage

Problem

An experimental apparatus has an upper chamber into which oil drops are sprayed over a plate with a positive charge. Drops can fall through a hole in the plate to a lower chamber, into which x-rays are beamed above a negatively charged plate. (1) X-ray irradiation causes drops to pick up electrons and become negatively charged. (2) The force of gravity pulls drops downward but is opposed by the electric field that pushes the negatively charged drops upward. A microscopic view shows drops of different sizes moving upward and downward.

.

Millikan’s oil-drop experiment to measure the charge of the electron. Small drops of oil are allowed to fall between electrically charged plates. Millikan measured how varying the voltage between the plates affected the rate of fall. From these data he calculated the negative charge on the drops. Because the charge on any drop was always some integral multiple of 1.602 10-19C, Millikan deduced this value to be the charge of a single electron.

Are the masses of the oil drops changed significantly when electrons accumulate on them?