calculate the pressure (in atm) of 2.50 Liters of a gas at 25 C if it has a volume of 4.50 Liters at STP

Harvey kept a balloon with a volume of 348 milliliters at 25.0˚c inside a freezer for a night.  when he took it out, its new volume was 322 milliliters, but its pressure was the same.  if the final temperature of the balloon is the same as the freezer’s, what is the temperature of the freezer? the temperature of the freezer is  kelvins.

Long term exposure to waves can cause sunburns and skin cancer. a) visible b) infrared c) gamma rays d) ultraviole

Estimate the molar mass of the gas that effuses at 1.6 times the effusion rate of carbon dioxide.