What is the mass in grams of 2.45×10 moles zinc

What is the empirical formula for c4h8o2

If an area has high air pressure and low humidity, what type of weather will it most likely have? plz !

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?