SCH4U - Balancing Chemical Equations - II

What is the main prerequisite before balancing chemical equations? (1)

• Your chemical formulas must be perfect, thus you must be able to recognize Ionic and Covalent compounds

How do you translate / write covalent compounds written as words into their chemical formulas?

1. Write the periodic symbol of the first non - metal with the subscript that matches the prefix from the name.

1. Write the periodic symbol of the second non - metal with the subscript that matches the prefix from the name.

Recall the Greek prefixes for covalent compounds and what number they represent from 1 - 10. Flip the card to confirm answers (20)

How is an Ionic Compound formed?

• Transfer of electrons between metals and non - metals

How is a covalent compound formed?

• Sharing of electrons between non - metals

What is a skeletal equation?

• A chemical equation where the correct formulas are written, but it is still not balanced.

Where do you place the numbers you need to when balancing? What is the name for these numbers?

• In front of the chemical entities you need to balance

• These are called “coefficients”

What is the end goal of balancing a chemical equation?

• Achieving equal amount of atoms of the same type on both sides of the reaction.

How do you know if a chemical equation is balanced? (1)

• There is an equal amount of atoms for each element on both sides

How can you tell if a chemical compound is covalent from words? (there are 2 ways)

• Look for the usage of Greek prefixes

• Determine if the constituent elements/atoms are both non - metals or not.

Which elements are diatomic gases? remember the mnemonic

• HNOFCl (Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine)

Which elements form the non - gaseous diatomic atoms and what are their states?

• Br (solid)

• I (liquid)

When balancing chemical equations, how do we view polyatomic ions?

• We treat them as one chemical entity; we do not individually count each of their atoms inside, or add the atoms within them to the total count of other atoms (for example, an oxygen in nitrate would not be counted as oxygen by itself). We look to balance the entire polyatomic ion.

When balancing chemical equations, should we balance polyatomic ions or metals first?

• polyatomic ions