Counting Atoms Lesson-Chem.

Counting Atoms

Chemistry HZ

Watch the video. Jot down important ideas in the sidebar of your notes next to counting atoms

Open Ended

What is something you remember from the counting atoms video?

Coefficient vs Subscript

• Coefficient: Numbers in front of a formula which gives the total number of compounds.

• Subscripts: The small number to the bottom right of an element, which tells the number of atoms of the element immediately before it.

Counting Atoms: Formulas with parenthesis

• The subscript on the outside of the parenthesis applies to everything within the parenthesis.

• Multiple any subscript on the inside of the parenthesis by the subscript outside the parenthesis

• multiply all numbers by the coefficient for a total number of atoms

Multiple Choice

What is the Coefficient?

• 4

• 3

• 1

• 0

Multiple Choice

What is the subscript of Nitrogen?

• 4

• 3

• 1

• 0

Fill in the Blank

How many elements are there: K₂HPO₄

Multiple Choice

How many atoms are there: C₆H₁₂O₆

• 3

• 6

• 12

• 24

Multiple Choice

How many atoms are there: N₂O

• 2

• 3

• 4

Multiple Choice

In the equation for photosynthesis, how many Hydrogen atoms are in glucose?

• 2

• 6

• 12

Multiple Choice

In the equation for photosynthesis, what is the coefficient for water?

• 1

• 2

• 6

• 12

Multiple Choice

Determine the number of Lithium (Li) atoms are in the following chemical formula: Li₂SO₄

• 1

• 2

• 4

Multiple Choice

Determine the number of Hydrogen (H) atoms are in the following chemical formula: 3H₂O

• 4

• 3

• 2

• 6