How do you find the molecular mass of the following compound?

To find the molecular mass of a compound, you sum the atomic masses of all the atoms in the molecule.

Here’s a detailed explanation, based on information from the video reference provided, and applied to the compound COCl₂ (phosgene):

Calculating Molecular Mass

Molecular mass, often called molecular weight, is the total mass of a molecule. It's calculated by adding the atomic masses of each atom within the molecule. These atomic masses are found on the periodic table and are often expressed in atomic mass units (amu).

Step-by-Step Guide with COCl₂ Example

The video reference uses COCl₂ as a primary example to illustrate how to calculate molecular mass:

1. Identify the elements and their quantities:

• In COCl₂, you have:
  • 1 carbon atom (C)
  • 1 oxygen atom (O)
  • 2 chlorine atoms (Cl)

2. Find the atomic mass of each element:

   • According to the video:
     • Carbon (C) has an atomic mass of 12.01 amu.
     • Oxygen (O) has an atomic mass of 16.00 amu.
     • Chlorine (Cl) has an atomic mass of 35.45 amu.

3. Multiply the atomic mass by the number of atoms of that element in the molecule:

   • Carbon: 1 atom * 12.01 amu/atom = 12.01 amu
   • Oxygen: 1 atom * 16.00 amu/atom = 16.00 amu
   • Chlorine: 2 atoms * 35.45 amu/atom = 70.90 amu

4. Add the masses together:

5. 01 amu (C) + 16.00 amu (O) + 70.90 amu (2 Cl) = 98.91 amu

6. Result:

• The molecular mass of COCl₂ is 98.91 amu.

Summary Table

Element	Number of Atoms	Atomic Mass (amu)	Subtotal (amu)
Carbon (C)	1	12.01	12.01
Oxygen (O)	1	16.00	16.00
Chlorine (Cl)	2	35.45	70.90
Total			98.91

Key Points

• Use the periodic table: Atomic masses are found on the periodic table.
• Multiply by quantity: Make sure to multiply the atomic mass by the number of atoms of that element present in the molecule.
• Units: Molecular mass is typically expressed in atomic mass units (amu).

By following these steps, you can determine the molecular mass of any compound.