Two moles of an unknown substance were shown to have a mass of 240g. what molecular mass does the substance have?

The goal of this experiment was to answer the question "what is the effect of a gas' temperature on its volume? " you formulated the hypothesis below. hypothesis: if a fixed amount of gas is heated, then the volume will increase because the heat will cause the molecules of gas to move faster and further apart. to test this hypothesis, you changed the of the gas between 0 and 100°c (273 and 373 k) and calculated the resulting of the gas.