Describe each type of matter as a pure substance (element), pure substance (compound), or mixture

Darla claims that the first periodic table developed by mendeleev was not completely accurate, so it is not useful at all. harmony argues that it establish the periodic table we use today, making it more credible. who is correct and why? darla is correct, because a model that has any mistakes should be thrown out. darla is correct, because a good model would not need to change. harmony is correct, because mendeleev’s model had all of the information correct in the first version. harmony is correct, because mendeleev’s model made predictions that came true.

At 450 mm hg a gas has a volume of 760 l, what is its volume at standard pressure

What is the molar mass of potassium nitrate, kno3