Potassium-40 decays to argon-40 with a half-life of 1.27 × 109 yr. The age of a mineral sample that has a mass ratio of 40ar to 40k of 0.812 is yr.

The age of the mineral sample is

Explanation:

The equation used to calculate rate constant from given half life for first order kinetics:

where,

= half life of the reaction =

Putting values in above equation, we get:

We are given:

Mass ratio of K-40 to Ar-40 = 0.812 : 1.00

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 = [1.00 + 0.812] = 1.812 grams

[A] = amount left after decay process = 1.00 grams

Putting values in above equation, we get:

Hence, the age of the mineral sample is

fire could start, buildings collapsing, and ash falling from the sky.

explanation:

this is because the buildings or plants could catch on fire and the buildings would most likely collapse. lastly ash would fall because all the burning would cause ash to fall from the sky.

hope this .

it's c. elements are placed in rows based on how may valencies electrons have.