2. If the half-life of Francium-233 is 22 minutes, how much time must elapse in order for 60 grams of a 64 gram sample to undergo decay? In other words, after how many minutes will you only have 4 grams of the original isotope
remaining?

88 minutes

Explanation:

64 g  ---> 32g  ---> 16g  ---> 8 g ---> 4 g

So in total, we have 4 half lives to reach 4.0 g

therefore, 4 x 22 minutes = 88 minutes

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.