Please help need honest answers don’t be cruel

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 ?

Acetylene gas c2h2 undergoes combustion to produce carbon dioxide and water vapor how many grams of water are produced by the same amount of c2h2?

When the mercury level in a barometer decreases that atmospheric pressure has