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Oxygen gas (O2) Molar mass and Molecular weight

The molar mass and molecular weight of Oxygen gas (O2) is 31.9988 g/mol.

The composition of the O2 formula is as follows:

Element Symbol Atomic Weight Atoms Total Atomic Weight Mass Percent
Oxygen O 15.9994 g/mol 2 31.9988 g/mol 100.0000%

 

The molar mass and molecular weight of Oxygen gas (O2)

How to find the molar mass of Oxygen gas (O2)?

The molar mass and molecular weight of Oxygen gas (O2) can be calculated in 4 steps.

Step I: Identify the different elemental atoms present in the O2 compound.

The given compound is O2. It comprises atoms from 1 different elements i.e., and Oxygen (O).

Step II: Find the atomic weight of each element in the O2.

Here is the list of atomic weights for all elements, let’s check the and Oxygen (O) atom’s atomic weight.
• The atomic weight of Oxygen (O) is 15.9994 g/mol.

atomic weight of each element in O2

Step III: Determine the number of atoms of each element present in the O2 compound.

As per the chemical formula, O2, It is made up of and 2 Oxygen atoms.

Element Number of Atoms
O (Oxygen) 2

Step IV: Calculate the molar mass of the Oxygen gas (O2) compound by applying the formula:

Formula to calculate Molar mass

For Oxygen gas (O2):

Molar mass = Σ [(Atomic weight of Oxygen (O) x Number of O-atoms)] in O2

Substituting into the above formula, the values determined in steps II and III:

Molar mass of O2 = [(15.9994 x 2)]

Molar mass of O2 = 31.9988 = 31.9988 g/mol

Result: The molecular weight and molar mass of Oxygen gas (O2) is 31.9988 g/mol.

FAQs

What is the mass percent composition of Oxygen (O) in Oxygen gas (O2)?

To find the mass percent of Oxygen in O2, follow the steps given below:
  • Determine the atomic weight of Oxygen i.e., 15.9994 g/mol.
  • Find the mass of Oxygen (O) in O2 by multiplying the atomic weight of an O-atom with the total number of O-atoms in O2 i.e., 2.

∴ Mass of Oxygen in O2 = 15.9994 x 2 = 31.9988 g/mol.

Mass Percent Composition (%) Formula = (Mass of Element in the Compound/Molar Mass of the Compound) x 100

∴ Mass percent of Oxygen in O2 = (Mass of Oxygen in O2/Molar mass of O2) × 100%
∴ Mass percent of Oxygen in O2 = (31.9988/31.9988) × 100% = 100.00 %

Result: O2 contains 100.00 % of Oxygen as per its chemical composition.

Mass percent Composition of O in Oxygen gas (O2)

 

What is the atomic percentage composition of elements in Oxygen gas (O2)?

Atomic percentage composition formula (%) = Number of atoms of a particular element in a compound/Total number of atoms in that compound

For O2:
• There’s 2 O-atoms.
• Total atoms in O2 = 2 = 2

The atomic percentage composition of elements in the compound is:

Atomic percentage of Oxygen (O) in O2:
= (2/2) * 100
= 100.00%

atomic percent composition in Oxygen gas (O2)

 

How many grams of Oxygen are present in 1 mole of O2?

There are 2 O-atoms in a O2 molecule.
• Atomic weight of a O-atom = 15.9994 g/mol
∴ Total mass of Oxygen in 1 mole of O2 = 2 x 15.9994 = 32.00 g.
Therefore there are 32.00 grams of Oxygen in 1 mole of O2.

 

What is the mass of 2 mol of O2?

The molecular mass of O2 is 31.9988 g/mol. This means 31.9988 grams of O2 are present per mole.
Therefore, we can find the mass of O2 in 2 moles as follows:
Moles = Mass/Molar Mass
∴ Mass of O2 = Moles x Molar mass
∴ Mass of O2 = 2 x 31.9988 = 64.00 g
Thus, the mass of 2 mol of O2 is 64.00 g.

 

If you have 22.3992 grams of O2, how many moles do you have?

∴ Moles = Mass/Molar mass
∴ Moles of O2 = 22.3992/31.9988 = 0.7000
Thus, there are 0.7000 moles of O2 in its 22.3992 grams.

 

What is the mass in kg of 5.33 x 1025 molecules of O2?

1 mole of a substance contains Avogadro number of particles i.e., 6.02 x 1023.
Therefore, the number of moles in 5.33 x 1025 molecules of O2 are:
∴ Moles of O2 = 5.33 x 1025/6.02 x 1023 = 88.6

Now that we have its number of moles, so, we can use the molar mass of O2 (31.9988 g/mol) to find its mass as shown below.

∴ Mass of O2 = Moles x Molar mass
∴ Mass of O2 = 88.6 x 31.9988 = 2834.78 g

Converting mass from grams (g) to kilograms (kg) gives us:

∴ Mass of O2 = 2834.78/1000 = 2.83 kg
The mass of 5.33 x 1025 molecules of O2 is 2.83 kg.

 

What is the molar mass and molecular weight of Oxygen gas (O2)?

O2 is composed of .
  • The atomic weight of Oxygen is 15.9994 g/mol.

To find the molecular mass of O2, one multiplies the atomic weight of each element by its number of atoms in the molecule and then sums the results.

∴ For O2, it’s (2 x 15.9994).

Therefore, the molar mass of Oxygen gas (O2) is 31.9988 g/mol.

How to calculate the molar mass of Oxygen gas (O2)

 

About the author

Vishal Goyal is the founder of Topblogtenz, a comprehensive resource for students seeking guidance and support in their chemistry studies. He holds a degree in B.Tech (Chemical Engineering) and has four years of experience as a chemistry tutor. The team at Topblogtenz includes experts like experienced researchers, professors, and educators, with the goal of making complex subjects like chemistry accessible and understandable for all. A passion for sharing knowledge and a love for chemistry and science drives the team behind the website. Let's connect through LinkedIn: https://www.linkedin.com/in/vishal-goyal-2926a122b/

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