A gas balloon has a volume of 80.0 mL at 300K , and a pressure of 50.0 kPa. if the pressure changes to 80.0 kPa and the temperature rises to 320 K, what is the new volume of balloon in milliliters

The zinc within a copper-plated penny dissolves in hydrochloric acid if the copper coating is filed down in several spots (so that the hydrochloric acid can reach the zinc). the reaction between the acid and the zinc 2h+(aq)+zn(s)→h2(g)+zn2+(aq) . when the zinc in a certain penny dissolves, the total volume of gas collected over water at 25 °c is 0.947 l at a total pressure of 743 mmhg . (vapor pressure of water is 23.78 mmhg at 25 °c .) what mass of hydrogen gas is collected? answer in appropriate significant figures