Beryllium (Be) and Calcium (Ca)
The correct subscript for the reaction would be two. Oxygen gas exists as a diatomic molecule in nature. Also, the subscript two would balance the reaction. In balancing reactions, it is important that the atoms on each side of the reaction is equal.
<u>Answer:</u> The tree was burned 16846.4 years ago to make the ancient charcoal
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:
where,
= half life of the reaction = 5715 years
Putting values in above equation, we get:
Rate law expression for first order kinetics is given by the equation:
where,
k = rate constant =
t = time taken for decay process = ? yr
= initial amount of the sample = 100 grams
[A] = amount left after decay process = 13 grams
Putting values in above equation, we get:
Hence, the tree was burned 16846.4 years ago to make the ancient charcoal