Answer: See Explanation
Step-by-step explanation:
The total pressure in a canister that contains oxygen gas at a partial pressure of 804 mm Hg depends on the other gases present in the canister. The total pressure of a gas mixture is the sum of the partial pressures of all the gases present in the mixture.
The partial pressure of a gas is the pressure that it would exert if it were alone in the container at the same temperature and volume. So, if the canister also contains other gases, we need to know their partial pressures in order to calculate the total pressure.
For example, if the canister contains only oxygen gas at 804 mm Hg and no other gases, the total pressure would be 804 mm Hg. However, if the canister also contains other gases such as nitrogen, helium, etc. with specific partial pressures, we have to sum all the partial pressures to get the total pressure.
Therefore, the total pressure in a canister that contains oxygen gas at a partial pressure of 804 mm Hg can only be determined by knowing the partial pressures of all the other gases present in the canister.