Question

The density of ${{O}_{2}}$ is maximum at:
A. STP
B. 273 K and 2 atm
C. 546 K and 1 atm
D. 546 K and 2 atm

Answer 1

Density of any material is defined as its mass per unit volume. Density generally tells us about how tightly matter is packed together. It is a unique physical property for a particular object and each substance has a specific density.

Complete Step by step solution: The ideal gas law equation generally defines the equation of state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions but it has some limitations too. The state of an ideal gas is determined by the macroscopic and microscopic parameters like pressure, volume, temperature. Equation of ideal gas is given by:
PV = nRT
Where P = Pressure, V = Volume of the ideal gas, n = amount of ideal gas measured in terms of moles, R = gas constant and T = Temperature.
Where n = $\dfrac{w}{M}=\dfrac{mass}{Molecular Weight}$
By putting the value of n in ideal gas equation
$PV=\dfrac{w}{M}RT$
Density of any substance is given by $\dfrac{w}{V}$ and denoted by the symbol $\rho$
Thus, $\rho =\dfrac{w}{V}=\dfrac{PM}{RT}$
This equation shows that density is directly proportional to pressure and inversely proportional to temperature so we can say that density is maximum at maximum pressure and minimum temperature.

Thus option B is the correct answer.

Note: STP stands for standard temperature and pressure. STP is most commonly used in performing the calculations on gases such as gas density. The standard temperature is 273 K, $0{}^\circ$Celsius or $32{}^\circ$ Fahrenheit and the standard pressure is 1 atm pressure.