<u>Answer:</u> The amount of sample left after 20 years is 288.522 g and after 50 years is 144.26 g
<u>Explanation:</u>
We are given a function that calculates the amount of sample remaining after 't' years, which is:

Putting values in above equation:


Hence, the amount of sample left after 20 years is 288.522 g
Putting values in above equation:


Hence, the amount of sample left after 50 years is 144.26 g
The statement which is true about the reactivity of element with 1S²2S²2P⁶3S¹ is
it is reactive because it has to lose one electron to have a full outermost energy level.
<u><em>Explanation</em></u>
- <u><em> </em></u>Element with 1S²2S²2P⁶3S¹ electron configuration is a sodium metal.
- sodium has one electron in the outermost energy level.
- for sodium to have a full outermost energy level ( 8 electrons) it loses the 1 electron in 3S¹ to form a positively charged ion. (Na⁺)
The correct question is as follows: 0.500 moles of potassium oxide is dissolved in enough water to make 2.00 L of solution. Calculate the molarity of this solution (plz help!)
Answer: The molarity of this solution is 0.25 M.
Explanation:
Molarity is the number of moles of a substance divided by volume in liter.
As it is given that there are 0.5 moles of potassium oxide in 2.00 L of water so, the molarity of this solution is calculated as follows.

Thus, we can conclude that molarity of this solution is 0.25 M.
Atomic weight is actually calculated by the sum of protons and neutrons of that atom. It is not equal to the number. You must add them for the result