This chart show the amount of radioactivity measured from three unknown isotopes.

which statement describes each of the isotopes?
isotope a was measured at day 24, isotope b was measured at day 6, and isotope c was measured at day 10.
isotope a was measured at day 18, isotope b was measured at day 4, and isotope c was measured at day 5.
isotope a was measured at day 24, isotope b was measured at day 8, and isotope c was measured at day 20.
isotope a was measured at day 30, isotope b was measured at day 6, and isotope c was measured at day 10.

Astudent is given a sample of a blue copper sulfate hydrate. he weighs the sample in a dry covered porcelain crucible and got a mass of 23.875 g for the crucible, lid, and sample. the mass of the empty crucible and lid was found earlier to be 22.652 g. he then heats the crucible to expel the water of hydration, keeping the crucible at red heat for 10 minutes with the lid slightly ajar. on colling, he finds the mass of crucible, lid, and contents to be 23.403 g. the sample was changed in the process to very light clue anhydrous cuso4. if there are again 100.0 g of hydrate, how many grams of cuso4 are in it? how many moles of cuso4? (hint: molar mass of cuso4 = 159.6 g / mole. what per cent of the hydrate is cuso4? you may convert the mass of cuso4 to moles.)

In what environment would mineral formation caused by high pressures and high temperatures most likely occur?

Asample of freon gas has a volume of 2.23 liters, a pressure of 4.85 kpa, and a temperature of -1.36°c. calculate the volume at a pressure of 1.38 kpa and a temperature of 5.5°c. (show work)