1) A piece of dry ice (CO2) has a mass of 23.50 g. It is dropped into an evacuated 2.00-L flask. What is the pressure in the flask at -7°C?
2)A sample of oxygen of mass 22.0 g is confined in a vessel at 2°C and 2000. torr. Then 2.50 g of hydrogen is pumped into the vessel at constant temperature. What will be the final pressure in the vessel (assuming only mixing with no reaction)?
3)A nitrogen sample occupies 236 mL at STP. If the same sample were collected over water at 25°C and 700. torr, what would be the volume of the gas sample? (Assume that vapor pressure of water at 25°C is 23.8 torr.)
4)Heating a 5.374-g sample of an ore containing a metal sulfide, in the presence of excess oxygen, produces 1.327 L of dry SO2, measured at 18.0°C and 791 torr. Calculate the percentage by mass of sulfur in the ore.