I put a spatula of blue crystals in a beaker of water, the water turned blue. Is this a physical or chemical change?

An object resting on a table weighs 100 n. with what force is the object pushing on the table? with what force is the table pushing on the object? explain how you got your answer.

3.09 lab: reaction of metals 1 which combinations of substances resulted in a chemical change? for each metal that participated in a chemical change, write the type of metal it is, based on your examination of the periodic table. were there any metallic compounds that did not react with either the acid or the base? write the type of metal, based on your examination of the periodic table. make a general statement about the reactivity of the metals in this experiment.

How many atoms or molecules are there in a mole of a substance?