a gas tank contains 15 moles of oxygen and 20 moles helium what is apertial pressure of helium in this 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.

What happens when an acid dissolves?

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?