Chemical Formulas and Elements

Which statement best describes a chemical formula?

• A list of physical properties of a substance

• A representation of a substance using symbols for its elements

• A diagram showing particle motion

• An equation that measures temperature

According to element symbol rules, which is the correct way to write the symbol for an element that uses two letters?

• Both letters lowercase

• Both letters capitalized

• First letter capitalized, second letter lowercase

• First letter lowercase, second letter capitalized

Using the examples shown, how many different elements are present in the chemical formula 3NaC2H3O2?

• 2

• 3

• 4

• 5

Which part of a chemical formula tells you the number of molecules present?

• The subscript after an element symbol

• The coefficient written at the beginning of the formula

• Parentheses around part of the formula

• The element symbols themselves

Based on the rule that the coefficient at the beginning of a chemical formula equals the number of molecules, how many molecules are represented by 3NaC2H3O2?

• 1

• 2

• 3

• 5

Which part of a chemical formula indicates how many atoms of a specific element are present in one unit of the substance?

• Coefficient

• Subscript

• Superscript

• Element name

If there is no subscript after an element’s symbol in a chemical formula, how many atoms of that element are present per formula unit?

• 0

• 1

• 2

• Depends on the coefficient only

What is the correct procedure to find the TOTAL number of atoms represented by a chemical formula with a coefficient?

• Add the coefficient to each subscript

• Multiply the subscripts by each other

• Add atoms of each element, then multiply the sum by the coefficient

• Ignore the coefficient and count subscripts only

Based on the examples table, how many total atoms are represented in the formula 3NaC2H3O2?

• 8

• 16

• 24

• 30

Using the counting rules, what is the total number of atoms in 4CO2?

• 3

• 8

• 10

• 12