STP (Standard Temperature and Pressure) conditions are defined as 0 degrees Celsius (273.15 Kelvin) and 1 atmosphere (1 ATM) of pressure. To determine the pressure of the gas at STP, we can use the ideal gas law equation:
PV = nRT
where: P = pressure V = volume n = number of moles of gas R = ideal gas constant T = temperature in Kelvin
Since the temperature is constant and the amount of gas remains the same, we can rearrange the equation as:
P1V1 = P2V2
where: P1 = initial pressure V1 = initial volume P2 = pressure at STP V2 = volume at STP
Given: P1 = 1.5 ATM V1 = 550 mL (converting to m^3: 550 mL = 0.55 L = 0.55 m^3) P2 = ? V2 = ?
Applying the equation:
P1V1 = P2V2
(1.5 ATM) * (0.55 m^3) = P2 * (1 m^3)
0.825 ATM*m^3 = P2 * 1 m^3
P2 = 0.825 ATM
Therefore, the pressure of the gas at STP is approximately 0.825 ATM.