Answer:
After 90 minutes 5.15625 g amount left from total of 165 g.
Explanation:
Given data:
Technetium-104 half life = 18.0 min
Total amount of sample = 165 g
Amount left after 90.0 min = ?
Solution:
First of all we will calculate the number of half lives passes.
Number of half lives = T elapsed / Half life
Number of half lives = 90 min /18.0 min
Number of half lives = 5
Amount left:
At time 0 = 165 g
At first half life = 165 g/ 2= 82.5 g
At 2nd half life = 82.5 g/2 = 41.2 g
At 3rd half life = 41.2 g/ 2 = 20.625 g
At 4th half life = 20.625 g/ 2 = 10.3125 g
At 5th half life = 10.3125 g /2 = 5.15625 g
Thus, after 90 minutes 5.15625 g amount left from total of 165 g.
0.00032 / 140000000
=0.000000000002
=2 x 10^-12
The correct reference for this isotope is A. Oxygen-18.
Answer: It is element nitrogen. It has an atomic number of 7 and the valence electron is 5. It needs 3 electrons to complete its octet state. That's why sometimes it has the oxidation number of -3 in ammonia.
