STP stands for Standard Temperature and Pressure, which is defined as a temperature of 0 degrees Celsius (273.15 Kelvin) and a pressure of 1 atmosphere (760 mmHg or 101.3 kilopascals). To find the volume of the gas at STP, we can use the combined gas law equation:
(P1 * V1) / (T1) = (P2 * V2) / (T2)
Where: P1 = Initial pressure of the gas (1800 mmHg) V1 = Initial volume of the gas (2 liters) T1 = Initial temperature of the gas (135 °C + 273.15 = 408.15 Kelvin) P2 = Final pressure at STP (1 atmosphere or 760 mmHg) V2 = Final volume at STP (what we need to find) T2 = Final temperature at STP (0 °C + 273.15 = 273.15 Kelvin)
Let's plug in the values into the equation and solve for V2:
(1800 mmHg * 2 L) / (408.15 K) = (760 mmHg * V2) / (273.15 K)
Simplifying the equation:
3600 mmHg L / 408.15 K = 760 mmHg * V2 / 273.15 K
Cross-multiplying:
3600 mmHg L * 273.15 K = 760 mmHg * V2 * 408.15 K
Dividing both sides by (760 mmHg * 408.15 K):
V2 = (3600 mmHg L * 273.15 K) / (760 mmHg * 408.15 K)
Canceling out the units:
V2 = 0.881 L
Therefore, the volume of the gas at STP would be approximately 0.881 liters.