True or false?equal masses of two different gases placed in containers of equal volume at equal temperature must exert equal pressures
true
True. According to the ideal gas law, which states that PV = nRT (where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature), the pressure exerted by a gas is directly proportional to the number of moles of gas present.
If we assume that the two different gases have equal masses, then, by the law of conservation of mass and using the molar mass of each gas, we can deduce that they also have an equal number of moles.
Since the volume and temperature are the same for both gases (as mentioned in the question), and the number of moles is equal, the pressures exerted by the two gases will also be equal.