Counting Atoms in Chemical Formulas

This video tutorial explains how to interpret chemical formulas by identifying elements, understanding subscripts, using coefficients, and recognizing the role of parentheses. It covers the rules for element symbols, the significance of subscripts in indicating the number of atoms, and how coefficients act as multipliers in chemical equations. The tutorial also demonstrates how to count atoms in complex formulas, such as ammonium sulfate, by applying these concepts.

What does a capitalized single letter in a chemical symbol represent?

• A compound

• A reaction

• A mixture

• An element

How many potassium atoms are in the formula KBr?

• 0

• 1

• 2

• 3

Tags

NGSS.MS-PS1-1

What does a subscript in a chemical formula indicate?

• Number of reactions

• Number of compounds

• Number of atoms of the element before it

• Number of molecules

In the formula 2NaCl, how many chlorine atoms are present?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-1

What role does a coefficient play in a chemical formula?

• Indicates a reversible reaction

• Acts as a multiplier for all elements that follow

• Signifies a catalyst

• Denotes physical states

Tags

NGSS.MS-PS1-5

In the formula Al2(CO3)3, how many total atoms of carbon are present?

• 12

• 6

• 9

• 3

Tags

NGSS.MS-PS1-1

How many oxygen atoms are in Al2(CO3)3?

• 3

• 6

• 9

• 12

Tags

NGSS.MS-PS1-1

In the formula (NH4)2SO4, how many hydrogen atoms are present?

• 12

• 8

• 16

• 4

Tags

NGSS.MS-PS1-1

What is the total number of sulfur atoms in (NH4)2SO4?

• 4

• 3

• 2

• 1

Tags

NGSS.MS-PS1-1

If the coefficient '2' is in front of (NH4)2SO4, how many nitrogen atoms are there?

• 8

• 6

• 4

• 2

Tags

NGSS.MS-PS1-1