The half-life of uranium-238 is 4.5 billion years. What is the decay constant for uranium-238? А) 1.72 х 10-7 yr-1 в) 1.65 x 10-8 yr-1 1.44 x 10-9 yr-1 (D 1.54 x 10-10 yr-1

Question 2 (20 pts) The decay of U-238 to Pb-206 can be used to estimate the age of inorganic matter. The half-life of U-238 is 4.5 X 10 years. In a particular rock sample, the ratio of the numbers of Pb-206 to U-238 atoms is 0.66. Assume all of the Pb-206 present is due to the decay of U-238. What is the age of the rock? -kt .693 -10 C=Coe Ty2: .693 K K= = 1.54 X10 4.5 410

σ=6

Using the T-xy diagram below estimate the bubble-point temperature (in degrees Celsius) and equilibrium vapor composition associated with 0.275 mole fraction ethanol. b. what happen to the bubble point as the mole fraction of ethanol increase? why? c. Describe what happening after about 0.75 mol fraction ethanol.