Your teacher asks you to follow the instructions in a lab to produce several known chemical reactions. during these procedures, you are required to record any observations that suggest chemical reactions have occurred. which of these list of observations best describes evidence of chemical reactions? a) a liquid melts and becomes a solid. b) when heated steam comes out of a test tube. eliminate c) a gas or solid is formed from two liquid solutions. d) the two chemicals separate and form two distinct layers.

This chart represents the melting point of several substance. what besy explains the high melting point of the salt?

The clouds are grey and ground is wet. a quantitative b qualitative

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.)