A balloon is inflated with 2.42 L of helium at a temperature of 27 degrees celsius. Later, the volume of the balloon has changed to 2.37 L at a temperature of 19 degrees celsius and a pressure of 99.7 kPa. What was the pressure when the balloon was inflated?

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u.s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?