A sample of pure radioactive isotope is left to decay. After 40.0 days, the 1 point sample is placed in a mass spectrometer, and it is determined that only
25% of the original isotope remains. How long is the half-life?

Which substance absorbs 58.16 kj of energy when 3.11 mol vaporizes? a)ch4 b)h2s c)co2 d)nacl

Which of these sequences lists the correct order for the creation of sedimentary rock from sediment? a. deposition, burial, compaction, cementation b. burial, deposition, compaction, cementation c. compaction, deposition, burial, cementation d. cementation, deposition, burial, compaction

If a gas has an initial pressure of 101kpa and a volume of 10l, then it expands to a volume of 20l, what is the new pressure?