Question

0.96g of a gas occupies a volume of 0.672L at STP. What is the identity of the gas?

A) Oxygen (O2)
B) Nitrogen (N2)
C) Hydrogen (H2)
D) Carbon Dioxide (CO2)

Answer 1

The identity of the gas is determined by calculating its molar mass using the given mass and volume at STP. The molar mass calculated is approximately 32 g/mol, which corresponds to Oxygen (O2).

Step-by-step explanation:

To determine the identity of the gas, we use the concept of molar volume at standard temperature and pressure (STP), which is 0°C and 1 atm. At STP, one mole of any ideal gas occupies 22.4 L. Given that 0.96 g of the gas occupies 0.672 L at STP, we can calculate its molar mass.

First, we determine the number of moles of the gas present using the given volume:

• Number of moles = Volume of gas at STP / Molar volume at STP = 0.672 L / 22.4 L/mol = 0.03 mol

Next, we find the molar mass of the gas knowing its mass and the amount in moles:

• Molar mass = Mass / Number of moles = 0.96 g / 0.03 mol = 32 g/mol

The molar mass corresponds to molecular oxygen (O2), which has a molar mass approximately equal to 32 g/mol. Therefore, the identity of the gas is Oxygen (O2).