As discussed in Raymond Chang’s introductory textbook “Chemistry,” a mole is a measure of molecules, equal to approximately 6.022x10^23 molecules, where the caret ^ refers to exponentiation. Using the ideal gas formula, you can find the number of moles of carbon dioxide (CO2) in a container if you know the other needed parameters and conditions. Above 150 pounds per square inch (PSI), or around 10 times normal atmospheric pressure, the ideal gas formula starts losing accuracy and the Van der Waals formula becomes increasingly preferable.
Thomas is incorrect because acceleration is a vector quantity that is defined as the rate at which an object changes its velocity. An object is accelerating if it is changing its velocity.