A 42.6-mL volume of hydrogen gas is collected over water at 20 degrees Celsius. A 42.0-mg sample of aluminum reacts with an excess of 6MHCl. The pressure of the "wet" hydrogen gas is adjusted to atmospheric pressure, a pressure of 750 Torr. Determine the percent by mass of aluminum in sample when the vapor pressure of water at 20 degrees Celsius is 17.5 Torr.