chemical equations

Chemical
Equations

• Scientists use chemical

Equations to represent atoms
and molecules and how they
change during a chemical or
physical change

State Symbols

• (s) = solid

• (l) = liquid

• (g) = gas

• (aq) = aqueous or dissolved in water

Chemical Equation

Chemical
Reaction
Description

• A chemical reaction takes place.

Solid iron is added to aqueous
hydrochloride acid and reacts to
form hydrogen gas and aqueous
iron chloride. For every mole of
iron and two moles of
hydrochloric acid that react,
87.9 kJ of heat is given off.

Balanced vs.
Unbalanced

• It is important to balance

chemical equations properly
because balanced equations are
useful for calculating amounts of
each compound or element that
are needed for a reaction or
should be produced during a
reaction.

Chemical reaction description

Tips for writing and balancing

Tips for writing and balancing

Tips for

writing and
balancing