Transcript Chemical Equation Terminology in Chemical Equations • Chemical reactions – one or more chemical changes that occur at the same time, it.

Chemical Equation
Terminology in Chemical Equations
• Chemical reactions – one or more chemical
changes that occur at the same time, it maybe
represented using equations which can be
written in words or symbols
• Reactants – pure substances that react in a
chemical change
• Products – pure substances formed in a
chemical change that has different properties
from those of the reactant
Terminology in Chemical Equations
• Symbolic Equations – set of chemical symbols and formula
that identify the reactants and products in a chemical
reaction
• Word equation – what we learned in 4.2!!
• Coefficients – integers are placed in front of the formulas or
a chemical symbol for an element. Is used to determine the
ratio between various compounds in a chemical reaction
• State of Matter – letters indicate the compounds’ states
–
–
–
–
(g) for gas
(l) for liquid
(s) for solid
(aq) for aqueous (dissolved in water)
Word
equation
REACTANTS
PRODUCTS
Methane + oxygen
carbon dioxide + water
Law of Conservation of Mass
• The law by a French chemist Antonie Lavisier
• States that mass is conserved in a chemical
reaction
• The total mass of products is always EQUAL to
the total mass of reactants in a chemical
reaction
Balanced Equations
Shows the identities of each pure substance involved
as well as the matching of number of atoms of each
elements on both sides of chemical equations
Skeleton Equation
Try This 
Answers
Skeleton Equation
Balanced Equation
5
3
4
3
10
8
10
Hints for writing word equations from
chemical equations
1) Nearly all elements that use chemical symbols
that are not compounds are written as is ex. Cu
for copper
2) Memorize Methane, Water, and Ammonia
3) Memorize the 7 diatomic elements which are all
non-metals
Example: hydrogen + nitrogen
Skeleton equation:
H2 + N2
Balanced equation:
3H2 + N2
ammonia
NH3
2NH3
7 Diatomic elements
• Turn to “Strategies for Balancing Equations”
on the second last page of chapter 4 notes
• Read through hints for balancing equatinos on
page 209 of textbook
Try This 
Answers
Answers