Arock contains 0.636 mg of 206pb for every 1.000 mg of 238u present. assuming that no lead was originally present, that all the 206pb formed over the years has remained in the rock, and that the number of nuclides in intermediate stages of decay between 238u and 206pb is negligible, calculate the age of the rock. (for 238u, t1/2 = 4.5 ✕ 109 years.)

in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.

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