How many grams of calcium nitride (Ca3N2) are produced when 4.00 g of nitrogen reacts with an excess of calcium? 3Ca + N2 → Ca3N2

How does kepler second law of planetary motion overthrow one of the basic beliefs of classical astronomy

Harry lives in a city, and he has a lung condition known as asthma. on certain days, harry has to stay inside because pollutants in the air make it difficult for him to breathe. which of these pollution sources are nonpoint sources that might bother harry if he goes outside? choose the two that apply.

Which of the following molecules is polar? c3h7oh c2h5cooh