When calculating the number of gas particles in the lungs using the ideal gas law, which constant is required?

• A. 8.314 J/mol·K
• B. 0.0821 L·atm/(mol·K)
• C. 1.987 cal/(mol·K)
• D. 62.36 L·torr/(mol·K)

Answer: (B)

To calculate the number of gas particles in the lungs using the ideal gas law (PV = nRT), it is essential to use the appropriate gas constant that matches the units employed for pressure and volume in the calculations.

In this context, the gas constant of 0.0821 L·atm/(mol·K) is suitable because it is commonly used when pressure is expressed in atmospheres (atm) and volume in liters (L). When applying the ideal gas law to biological systems, such as calculating gas behavior in the lungs, the quantities are often measured in these conventional units. The pressure exerted by gases within the lungs when breathing can effectively be expressed in atm, making this constant the ideal choice.

The other constants provided, like 8.314 J/mol·K and 1.987 cal/(mol·K), relate to different unit systems and are less applicable for this scenario where pressure is being measured in atmospheres rather than joules or calories. Similarly, 62.36 L·torr/(mol·K) is also suited for a different pressure unit (torr) and is less commonly used in typical biological gas calculations involving the lungs compared to atm.

Therefore, using the constant that corresponds directly with the