In which of the following locations would the air most likely be at standard temperature and pressure (STP)?

• A. A mountaintop observatory with a temperature of 10°C and a pressure of 0.7 atm
• B. A laboratory at sea level with a temperature of 0°C and a pressure of 1 atm
• C. A deep underground mine with a temperature of 25°C and a pressure of 2 atm
• D. A desert at noon with a temperature of 35°C and a pressure of 1.2 atm

Answer: (B)

Verified step by step guidance

1. Recall the definition of standard temperature and pressure (STP), which is a temperature of 0°C (273.15 K) and a pressure of 1 atm.
2. Examine each location's given temperature and pressure values and compare them to the STP conditions.
3. For the mountaintop observatory: temperature is 10°C (which is higher than 0°C) and pressure is 0.7 atm (which is lower than 1 atm), so it does not match STP.
4. For the laboratory at sea level: temperature is 0°C and pressure is 1 atm, which exactly matches the STP conditions.
5. For the deep underground mine and the desert: both have temperatures and pressures that differ significantly from STP, so they are not at standard temperature and pressure.