Final answer:
A fixed fire extinguishing system approved by the U.S. Coast Guard can replace multiple portable B-I fire extinguishers, and the number varies by system specifics. When discussing the increase in pressure within a fire extinguisher left in a hot car, use Gay-Lussac's Law to calculate the new pressure at a higher temperature. Modern fire extinguishing systems use different agents for improved safety and effectiveness.
Step-by-step explanation:
A U.S. Coast Guard approved installed fire extinguishing system is typically designed to replace a certain number of portable B-I fire extinguishers. The exact number can vary depending on the specifics of the system and the requirements it meets. For boats, a single fixed fire extinguisher system can often replace the need for multiple portable fire extinguishers. However, the question at hand is about the increase in internal pressure of a fire extinguisher when exposed to high temperatures. It's important to know that fire extinguishers, such as those containing CO2 or dry-cleaning solvent, should not be exposed to extreme heat to prevent a hazardous increase in pressure that could lead to failure or explosion.
Regarding the example given in Exercise 11.4.3, to calculate the new internal pressure of the fire extinguisher when the temperature rises to 71.1°C (160°F), we would use Gay-Lussac's Law, which states that pressure is directly proportional to temperature when volume and mass remain constant. The formula for Gay-Lussac's law is P1/T1 = P2/T2. Given the initial pressure (P1) of 20.0 atm and initial temperature (T1) of 21°C, we could solve for the final pressure (P2) when the temperature is at 71.1°C. Always remember to convert temperatures to Kelvin when using this equation.