0.15 mL of a solution made from 0.381 g of unknown in 500.00 mL of pentane on a pan of water. After all the pentane evaporated a 24.36 cm2 monolayer of unknown remained on the surface of the water. If the density of the unknown was 0.719 g/mL what was the thickness of the monolayer in micrometers?

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.

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.

The number of neutrons is equal to the atomic number minus the atomic mass. a. true b. false