Ch.19 - Nuclear ChemistryWorksheetSee 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: A moon rock collected by a U.S. Apollo mission is estimated to be 4.30 billion years old by uranium/lead dating. Assuming that the rock did not contain any lead when it was formed, what is the current

Solution: A moon rock collected by a U.S. Apollo mission is estimated to be 4.30 billion years old by uranium/lead dating. Assuming that the rock did not contain any lead when it was formed, what is the current

Problem

A moon rock collected by a U.S. Apollo mission is estimated to be 4.30 billion years old by uranium/lead dating. Assuming that the rock did not contain any lead when it was formed, what is the current mass in grams of  206Pb per 1.260 g of  236U in the rock? The half-life of  236U is t1/2 = 4.47 x 109 years.

Solution

We’re being asked to determine the mass of 206Pb in a moon rock with 1.260 g 236U


Recall that radioactive/nuclear decay of isotopes follows first-order kinetics, and the integrated rate law for first-order reactions is:



where:

[N]t = concentration at time t

k = decay constant

t = time

[N]0 = initial concentration


Also, recall that half-life is the time needed for the amount of a reactant to decrease by 50% or one-half


The half-life of a first-order reaction is given by:



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