Do only chemical reactions get colder/hotter? What is happening when potassium chloride dissolves?
• What do we think is happening when we put potassium chloride in
water? Is it dissolving?
What does dissolving even mean?
Is this phenomenon similar to or different from the chemical reactions
we have already seen?
• Is this a physical change or a chemical reaction? What evidence would
we need to collect to be able to know if it was one or the other?

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.)

If blood contains 150g of hemoglobin per liter of blood, how much hemoglobin would be contained in 10 ml of blood

What causes most sediment to wash or fall into a river