You are dating rocks by their proportion of parent isotope potassium-40 (half-life time 1.25 billion years) and daughter isotope argon-40. If the rock initially was made of only potassium-40, find the age for each of the following (explain your reasoning): a) A rock containing equal amount of potassium-40 and Argon-40. b) A rock that contain three times as much argon-40 as potassium-40

12 is it do you think so

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o