A volcanic eruption melts a large area of rock, and all gases are expelled. After cooling, 40Ar (atomic number 18) accumulates from the ongoing decay of 40K (atomic number 19) in the rock (t1/2 = 1.25 × 109 yr). When a piece of rock is analyzed, it is found to contain 1.07 mmol of 40K and 1.45 mmol of 40Ar. How long ago did the rock cool? Enter your answer in scientific notation.

The time is 1.545x10⁹ years

Explanation:

the solution is attached in the Word file

convalent bond :

is a chemical bond formed by the sharing of electron between 2 atoms.

it is the direct chemical bond between 2 atoms.

in bond formation atoms are involved here.

electrovalent bond:

is a chemical bond defined as electroststic attraction between 2 atoms.

it is the electrostatic attraction between 2 atoms.

in bond formation, ions are involved here.

hope it

and ur welcm

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there is none because earth is stationary and flat.