A sample of neon gas is held in a rigid 1.814L container with a pressure of 1.273atm at 25 C.193g of an unknown gas is added to the container.

A sample of neon gas is held in a rigid 1.814L container with a pressure of 1.273atm at 25 C. 3.193g of an unknown gas is added to the container. The temperature remains constant, but the pressure rises to 2.386atm. What is the molar mass of the added gas?