Ascientist digs up sample of arctic ice that is 458,000 years old. he takes it to his lab and finds that it contains 1.675 grams of krypton-81.

if the half-life of krypton-81 is 229,000 years, how much krypton-81 was present when the ice first formed?

use the formula n = n0 .

How many atoms are there in 5.70 mol of mg

Which states of matter have particles that move independently of one another with very little attraction?

Select the correct value for the indicated bond angle in each of the compounds. o−o−oo−o−o angle of o3 90° 109.5° < 109.5° 120° < 120° 180° f−b−ff−b−f angle of bf3 180° < 109.5° < 120° 120° 109.5° 90° f−o−ff−o−f angle of of2 < 120° 120° 90° 109.5° 180° < 109.5° cl−be−clcl−be−cl angle of becl2 90° 109.5° 180° 120° < 109.5° < 120° f−p−ff−p−f angle of pf3 90° 109.5° < 109.5° 180° 120° < 120° h−c−hh−c−h angle of ch4 90° < 109.5° 180° 120° < 120° 109.5°