
60g after 3 hours, 30g after 6 hours and 15g after 9 hours
Explanation:
Weight of the radioactive sample = 120g
half life time period = 3 hours
(a) The weight of sample after 3 hours

The fraction of sample left

Mass of the sample left

<u>6</u><u>0</u><u>g</u><u> </u><u>of</u><u> </u><u>sample</u><u> </u><u>is</u><u> </u><u>left</u><u> </u><u>after</u><u> </u><u>3</u><u> </u><u>hours</u>
(b) The weight of sample after 6 hours

The fraction of the sample left

Mass of the sample left

<u>3</u><u>0</u><u>g</u><u> </u><u>of</u><u> </u><u>sample</u><u> </u><u>is</u><u> </u><u>left</u><u> </u><u>after</u><u> </u><u>6</u><u> </u><u>hours</u>
(c) The weight of sample after 9 hours

The fraction of sample left

Mass of sample left

<u>1</u><u>5</u><u>g</u><u> </u><u>of</u><u> </u><u>sample</u><u> </u><u>is</u><u> </u><u>left</u><u> </u><u>after</u><u> </u><u>9</u><u> </u><u>hours</u><u>.</u>
Crystallization is a physical change from liquid form to solid form. It is the opposite of melting. This is done by creating a supersaturated solution. You add more solute exceeding its capacity and heat so that all will dissolve. Then, when you cool it down with an aid of the ice, solid crystals will eventually form. The bigger the container the ice, the faster is the rate of crystallization and the bigger the solid crystals would be.
One deals with electrons while the other protons.