14. Are the atoms conserved during a chemical change even though new molecules are made? Use evidence from the PhET to support your answer.

When the following equation is balanced using the smallest possible integers, what is the coefficent of oxygen gas? c7h16o(g) + o2(g) → co2(g) + h2o(g) -1 -5 -8 -16 -21

Which statements describe polyatomic ions? check all that apply. polyatomic ions have many charges. polyatomic ions have one overall charge. polyatomic ions repel other ions to form ionic bonds. polyatomic ions attract other ions to form ionic bonds. polyatomic ions are made up of only one type of atom. polyatomic ions are made up of two or more types of atoms.

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.)