A high-pressure gas cylinder contains 60.0 L of toxic gas at a pressure of 1.30 107 N/m2 and a temperature of 15.0°C. Its valve leaks after the cylinder are dropped. The cylinder is cooled to dry ice temperatures (−78.5°C), to reduce the leak rate and pressure so that it can be safely repaired.

(a) What is the final pressure in the tank, assuming a negligible amount of gas leaks while being cooled and that there is no phase change? Apply the ideal gas law for the initial and final situations. N/m2

(b) What is the final pressure if one-tenth of the gas escapes? N/m2

(c) To what temperature must the tank be cooled to reduce the pressure to 1.00 atm (assuming the gas does not change phase and that there is no leakage during cooling)?