Name____________________

Section___________________

Use the data in the table to answer the following questions

Substance	mass at t=0	mass at t=27 minutes
X	250 gm	203 gm
Y	1068 gm	534 gm
Z	56 gm	9 gm

1. Which substance has the highest decay rate constant? Explain.

2. Find the half life for substance Z.

3.How much energy will be liberated when 5 grams of mass is converted to energy, according to Einstein?

4. Explain the meaning of the term isotope and give two examples of isotopes.

5. What are the three ways in which an unstable radioisotope can become a stable isotope?