Problem 5
It took 75 y for \(10.0 \mathrm{~g}\) of a radioactive isotope to decay to \(1.25 \mathrm{~g}\). What is the half-life of this isotope?
Problem 5
Radioactive strontium is dangerous because it can chemically replace calcium in the human body. The bones are particularly susceptible to radiation damage. Write the nuclear equation for the beta emission of strontium-90.
Problem 6
Write the nuclear equation for the beta emission of iodine-131, the isotope used to diagnose and treat thyroid problems.
Problem 6
A small asteroid crashes to Earth. After chemical analysis, it is found to contain \(1 \mathrm{~g}\) of technetium-99 to every \(3 \mathrm{~g}\) of ruthenium-99, its daughter isotope. If the half-life of technetium-99 is 210,000 y, approximately how old is the asteroid?
Problem 6
Describe a beta particle. What subatomic particle is it equivalent to?
Problem 6
It took \(49.2 \mathrm{~s}\) for \(3.000 \mathrm{~g}\) of a radioactive isotope to decay to \(0.1875 \mathrm{~g}\). What is the half-life of this isotope?
Problem 6
A sample of curium has an activity of \(1,600 \mathrm{~Bq}\). If the half-life of curium is \(24.0 \mathrm{~s}\), how long before its activity is \(25.0 \mathrm{~Bq}\) ?
Problem 7
If a radioactive sample has an activity of \(65 \mu \mathrm{Ci}\), how many disintegrations per second are occurring?
Problem 7
A common uranium compound is uranyl nitrate hexahydrate \(\left[\mathrm{UO}_{2}\left(\mathrm{NO}_{3}\right)_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O}\right] .\) What is the formula mass of this compound?
Problem 7
What are gamma rays?
