Approximately what percentage of Rb-87 will have decayed to Sr-87 when the rock is 3 billion years old? After 0.02 half-
lives
After 0.04 half-
lives
After 0.06 half-
lives
After 0.08 half-
lives
percent of Rb-87
remaining
98.623
97.265
95.926
94.606

6what is the importance of water on earth? a) it keeps the top layer of the geosphere cool b) it allows life to exist c) it provides ice at the poles d) it creates earth's blue color from space

A100 kmol/h stream that is 97 mole% carbon tetrachloride (ccl4) and 3% carbon disulfide (cs2) is to be recovered from the bottom of a distillation column. the feed to the column is 16 mole% cs2 and 84% ccl4, and 2% of the ccl4 entering the column is contained in the overhead stream leaving the top of the column. calculate the mass and mole fractions of ccl4 in the overhead stream, and determine the molar flow rates of ccl4 and cs2 in the overhead and feed streams. 12. mw_ccla- 153.82; mw_cs2-76.14.

Measurements that have similar values are: a. usually accurate b. sometimes accurate c. always accurate d. never accurate