Gram Formula Mass

Gram Formula Mass

Finding the mass of a compound

Multiple Choice

What is the mass of K?

• 39

• 19

• +1

• 40

Multiple Choice

What is the mass of Cl?

• -1

• 17

• 35

• 12

Open Ended

Based on the answers to the first two questions, K has a mass of 39 and Cl has a mass of 35, predict the mass of KCl?

Gram Formula Mass

• gram formula mass (formula mass): the mass of one mole of a compound.

Steps to Finding the Gram Formula Mass?

• Step 1: List all of the elements that makeup the compound (remember each element consist of a capital letter)

• Step 2: Look up the mass of each of the elements on the periodic table of elements and round to the nearest whole number.

• Step 3: Determine the number of atoms of each element type in the compound.

• Step 4: Multiply each of the element’s atomic mass by the number of atoms.

• Step 5: Add all the products to determine the molar mass.

Example 1:

CaCl₂

Multiple Choice

How many Ba atoms are present in the compound Ba₃(PO₄)₂

• 2

• 3

• 4

• 8

Example 2:

Ba₃(PO₄)₂