A weather balloon contains 5600m3 of helium (He) at a pressure of 1.25 × 105 Pa. The temperature of the helium is 7C ◦ . Data regarding helium can be found in the periodic table of elements. a) What is the mass (in kg) of the helium in the balloon ? b) The balloon rises and expands to a new volume of 7200 m3 At the same time,the temperature drops to −5C ◦ . Calculate the new pressure of the gas.
