TIESULUI
Carboniferous
Jurassic
Thassic
Permian
Pennsylvanian
Mississippian
Devonian
Silurian
Ordoviciantes
Cambran
Precambrian
Paleozoic
Which method is most likely used to identify what happened before the start of the Paleozoic era?
O
Scientists study fossils from the Jurassic period.
Scientists observe index fossil records of the Mesozoic era.
Scientists examine fossil evidence during the Precambrian time
Scientists explore the emergence of mammals and humans in the Cenozoic era.

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.)

Achemist 16 drop copper metal from copper chloride solution. the chemist place is 0.50 g of aluminum foil in a solution containing 0.75 g of copper (ii) chloride. a single replacement reaction takes place. which statement explains the maximum amount of copper that the chemist can extract using this reaction?

Which type of precipitation would most likely form when the surface air temperature is slightly below freezing and the air temperature increases as you move upward away from the ground?