Question

What is the density of oxygen gas at NTP?

Answer 1

Hint: The NTP is also defined in terms of STP. The density could be known by dividing the mass to the volume. Find out the molar mass of oxygen, and volume of gas at NTP must be known. The atomic mass of oxygen is 16 u.

Complete step by step solution:

a) First, let us know about the NTP. The NTP is known as normal temperature and pressure. The temperature of 293.15 K, and pressure of 1 atm is considered in the NTP.

b) As we know, the molar volume of an ideal gas at STP is same as the NTP, i.e. 22.4 L for one mole of a gas.

c) Now, we have to find the density of oxygen. The molar mass of oxygen gas (O$_2$) is equal to 32g/ mol. As, oxygen gas represents the diatomic molecule.

d) So, now we have the molar mass of the gas, divide it by 22.4 L/mol to attain the density.

e) Thus, Density = $\dfrac{Mass}{Volume}$ = $\dfrac{32g/mol}{22.4 L/mol}$ =1.428g/L

So, the density of oxygen gas at NTP is 1.42 g/L.

Note: Sometimes, we get confused between the STP, and NTP. The STP is standard temperature and pressure, i.e. 273.15 K, and 1 atm respectively; whereas in case of NTP pressure is 1 atm only, but the temperature is 293.15 K. In case of NTP and STP, molar volume of an ideal gas is 22.4 L only. There is no need for confusion in these both terms.