Ahe+ ion emits a photon with a frequency of 9.86e15 hz. if the energy of the initial state of the he+ ion was -2.18e-18 j, calculate the energy of the final state. express answer in scientific notation.

Solutions of sodium carbonate and silver nitrate react to form solid silver carbonate and a solution of sodium nitrate. a solution containing 3.50 g of sodium carbonate is mixed with one containing 5.00 g of silver nitrate. how many grams of sodium carbonate, silver nitrate, silver carbonate, and sodium nitrate are present after the reaction is complete?

Which statement would indicate the presence of an acid

Equal numbers of moles of he(g), ar(g), and ne(g) are placed in a glass vessel at room temperature. if the vessel has a pinhole-sized leak, which of the following will be true regarding the relative values of the partial pressures of the gases remaining in the vessel after some of the gas mixture has effused?