Which of the following are evidence that a chemical reaction has occurred? A. Two liquids are combined and a gas is released
B. A substance is added to water and dissolves
C. Two liquids are combined and a solid precipitate forms
D. A new substance is formed
E. A single reactant changes from a liquid to a solid

Which statement justifies that phosphine (ph3) is a polar molecule?

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.

Joe shines white light into a bowl half full of water at an angle of incident of 27.5°. calculate the angle of refraction in the water given the indices of refraction for air and water are 1.00 and 1.36, respectively.