Aballoon contains 5l of oxygen at a pressure of 90 kpa. how much oxygen will the ballon contain if the pressure is lowered to 67 kpa.

We have that all (ideal) gases obey the fundamental gas equation: PV=nRT where P is the Pressure, V is the Volume, n is the number of moles, R is a universal constant and T is the temperature in Kelvin. In this process, we have that both the number of moles and the temperature stays the same. So if we denote by i the initial conditions and by f the final conditions of the gas, we have: . Hence, if we solve for the final Volume we get: . Now we know all the other variables; substituting we get that the final volume is 6.7 L (6.716 L ).

It has to be b i hope this

The molar mass of a substance is defined as the mass of 1 mol of that substance, expressed in grams per mole, and is equal to the mass of 6.022 × 10 23 atoms, molecules, or formula units of that substance.