L 39 Counting Atoms in Chemical Formulas

Counting Atoms in Chemical Formulas

Introduction

• Chemical formula are used to represent the composition of elements and compounds

• Qualitative information of a formula shows the types of atoms (or ions) that make up the substance.

• Quantitative information of a formula shows how amhy of each atom (or ions) is in the formula. The number of each atom in a formula is shown with a subscript.

• Subscript in a chemical formula is the whole number written on the bottom of each atom in a formula.

Examples

Co ..................... (cobalt)

CO ..................... (carbon monoxide)

H₂O .................. (dihydrogen monoxide)

Ca(NO₃)₂............. (Calcium nitrate)

Multiple Select

How many atoms (in total) are found in the hydrate (NH₄)₃PO₄*5H₂O?

• 10

• 20

• 30

• 35

Multiple Select

How many different kinds of atoms are present in NH₄NO₃?

• 7

• 9

• 3

• 4

Multiple Select

How many Nitrogens are present in NH₄NO₃?

• 1

• 2

• 3

• 4

Multiple Select

How many atoms (total atoms) are present in NH₄NO₃?

• 7

• 8

• 9

• 10

Multiple Select

How many hydrogen atoms are found in the hydrate (NH₄)₃PO₄*5H₂O?

• 12

• 19

• 22

• 14

Multiple Select

How many different types of atoms are found in the hydrate (NH₄)₃PO₄*5H₂O?

• 6

• 5

• 3

• 4

Multiple Select

In the compound Al₂S₃ the mole ratio of Aluminum ion to sulfur ion is

• 2:3

• 3:2

• 13:16

• 27:16

Multiple Select

The ratio of ammonium ion to phosphate ion found in the hydrate (NH₄)₃PO₄*5H₂O is

• 1:1

• 1:2

• 3:1

• 3:5