Unit I: CHEMICAL REACTIONS

I.5. Using Chemical Word Equations

Words Balanced Chemical Equations

Need to Remember the difference between ionic and covalent (molecular)

If Ionic – use charges If Covalent – use prefixes

Words Balanced Chemical Equations

Diatomics AGAIN!!! N2, O2, F2, Cl2, Br2, I2 and H2

In a balanced chemical equation these elements are ALWAYS found in their diatomic or molecular form!!!!!!!!!!

Phases

Sometimes a chemical reaction will also show the phases in which the reactants and products exist (s) – solid {crystals, powder,

precipitate} (l) – liquid (g) – gas (aq) – aqueous (water solution)

Words Balanced Chemical Equations

General Rules1. Write the formulas of the compounds

2. Don’t forget your diatomics O must be O2

3. Add phases (s), (l), (g), (aq) if indicated

4. Balance your chemical equations as before

Precipitate

A precipitate is used to refer to a solid formed when two liquid or aqueous solutions react.

Precipitate

Example 1

aluminum chloride is mixed with potassium carbonate and aluminum carbonate and potassium chloride are formed. Write a balanced equation.

Example 2

Aluminum metal reacts violently with bromine to produce aluminum bromide. Write a balance equation.

Example 3

Sodium reacts quickly with water to produce hydrogen gas and sodium hydroxide

Example 4

Nitrogen monoxide reacts with oxygen to produce nitrogen dioxide.

Example 5

Magnesium sulphate heptahydrate decomposes to

form water and magnesium sulphate.

Acid Review

Name Formula

hydrochloric acid HCl

nitric acid HNO3

sulphuric acid H2SO4

acetic acid CH3COOH

phosphoric acid H3PO4

Hebden

Do Exercises 57 (a-e), 58, 59, 60 and 61 on p. 113-114 {include phases where indicated}

Do problem set 2 on page 6 in your student notebook

Do Hand-In Assignment #7 – Chemical Equations