Final answer:
The warning on the can is to prevent overheating that can lead to explosions. Using Gay-Lussac's law, the new pressure of gas in a can left at 50 °C is about 391.5 kPa.
Step-by-step explanation:
(a) The warning "Store only at temperatures below 120 °F (48.8 °C). Do not incinerate." is placed on cans containing pressurized gas because high temperatures can increase the pressure inside the can to dangerous levels. This can lead to the can rupturing or exploding, causing injury or damage. Incineration is extremely dangerous as it would expose the can to very high temperatures and almost certainly lead to an explosion.
(b) To calculate the new pressure in the can when the temperature increases to 50 °C, we can use the Gay-Lussac's law of pressure-temperature relationship, which states that the pressure of a gas is directly proportional to its absolute temperature, provided the volume is constant. The formula for Gay-Lussac's law is P1/T1 = P2/T2, where P1 and T1 are the initial pressure and temperature, and P2 and T2 are the final pressure and temperature.
Initial conditions: P1 = 360 kPa, T1 = 24 °C + 273.15 = 297.15 K
Final conditions: T2 = 50 °C + 273.15 = 323.15 K
Calculating new pressure: P2 = (P1 × T2) / T1 = (360 kPa × 323.15 K) / 297.15 K = 391.5 kPa approximately
Therefore, the new pressure in the can is about 391.5 kPa when it is left in a car that reaches 50 °C.