If the pressure and temperature of a gas remain constant, what would cause the the volume to increase?
A. increase in the molecular mass
B. the number of moles of the gas increases
C. the partial pressure of the gas increases
D. all of the above

The increase in the number of moles of gas particles would cause the volume to increase at constant pressure and temperature.

Explanation:

The kinetic energy or motion of gas particles are governed by four laws named on the founder of those laws. The first law termed as Charle's law defines the direct proportional relation between volume of the gas particles with temperature at constant pressure and number of moles. Then comes the Boyle's law which provides the inverse relation of volume with pressure of the gas molecules at constant temperature and number of moles.

But the volume also depends on the number of moles of the gas particles as stated by Avagadro's law. According to this law, if there is a an increases in the number of gas molecules then there will increase in the volume provided that the temperature and pressure is constant.

Thus, the increase in the number of moles of gas particles would cause the volume to increase at constant pressure and temperature.

c. orbital shape i hope this is correct