Phosphoric acid, a mild acid used among other things as a rust inhibitor, food additive, and etching agent for cavity repair by dentists, can be made from elemental phosphorus in a two step process. in the first step, phosphorus and oxygen react to form diphosphorus pentoxide: in the second step, diphosphorus pentoxide and water react to form phosphoric acid : suppose the yield of the first step is and the yield of the second step is . calculate the mass of phosphorus required to make of phosphoric acid. be sure your answer has a unit symbol, if needed, and is rounded to the correct number of significant digits.

Which type of orbits are found in the principal energy level n = 2 a - s b - s, f c - s, d d - s, p e - s, p, d

Many bird species build nests in which they raise their offspring. one of these species is known as the magnolia warbler. breeding pairs of magnolia warblers build nests out of pieces of grass and twigs. the female warbler will then lay her eggs in the nest and sit on the eggs for a few weeks until they hatch. after the offspring have hatched, the female will continue to sit on the newborn chicks to keep them warm. both the male and the female bring food for the offspring to eat until the young are mature enough to find food on their own. which of these most likely describes why birds such as the magnolia warbler build nests in which to raise their offspring? a. nest building decreases the amount of energy used by the parent birds to raise their offspring to adulthood. b. nest building increases the probability that the offspring will survive and eventually produce offspring of their own. c. nest building decreases the amount of food that the offspring require the adult birds to provide. d. nest building increases the probability of the offspring being located by airborne predators.

Ahelium balloon contains 16.9 l of helium at stp. how many atoms of helium are in the balloon