Answer:
Mason notices that his boat sinks lower into the water in a freshwater lake than in the ocean. What could explain this?
Explanation:
The freshwater has less density then the ocean!
Answer :
121.5 <span>
μCi
Explanation : We have Ce-141 half life given as 32.5 days so if the activity is 3.8 </span><span>μci after 162.5 days of time elapsed we have to find the initial activity.
We can use this formula;
</span>

3.8 /

=

((0.693 X 162.5 ) / 32.5) = 121.5
<span>
On solving we get, The initial activity as 121.5 </span>μci
The compound is Al2O3. The ratio of aluminum to oxygen is 2:3.
They move through the membrane