Chemical Reactions
SNC2D
Changes
A change in which no new substances are formed
is called a ?
Changes
A change in which no new substances are formed
is called a physical change.
Changes
A change in which no new substances are formed
is called a physical change.
e.g. ice melting
(both ice and water
are H2O)
Changes
A change in which new substances are formed is
called a ?
Changes
A change in which new substances are formed is
called a chemical change or chemical
reaction.
Changes
A change in which new substances are formed is
called a chemical change or chemical
reaction.
Signs and Symptoms
Recall the signs that a chemical reaction may have
occurred:
Signs and Symptoms
Recall the signs that a chemical reaction may have
occurred:
 heat produced or absorbed
Signs and Symptoms
Recall the signs that a chemical reaction may have
occurred:
 heat produced or absorbed
 light or sound produced
Signs and Symptoms
Recall the signs that a chemical reaction may have
occurred:
 heat produced or absorbed
 light or sound produced
 colour change
Signs and Symptoms
Recall the signs that a chemical reaction may have
occurred:
 heat produced or absorbed
 light or sound produced
 colour change
 gas produced
Signs and Symptoms
Recall the signs that a chemical reaction may have
occurred:
 heat produced or absorbed
 light or sound produced
 colour change
 gas produced
 precipitate formed in solution
Equations
Chemical reactions can be represented by either:
Equations
Chemical reactions can be represented by either:
 word equations using the names of the
chemicals (e.g. carbon dioxide, water)
Equations
Chemical reactions can be represented by either:
 word equations using the names of the
chemicals (e.g. carbon dioxide, water)
or
 chemical equations using the formulas of the
chemicals (e.g. CO2, H2O)
Reactants
The substances that are reacting are called ?
Reactants
The substances that are reacting are called
reactants and are written on the left side of the
equation. There may be only one; if there is
more than one, they are separated by ?
Reactants
The substances that are reacting are called
reactants and are written on the left side of the
equation. There may be only one; if there is
more than one, they are separated by + signs.
Reactants
The substances that are reacting are called
reactants and are written on the left side of the
equation. There may be only one; if there is
more than one, they are separated by + signs.
e.g.
carbon dioxide + water
CO2
+ H2O
Products
The new substances formed in the reaction are
called ?
Products
The new substances formed in the reaction are
called products and written on the right side of
the equation.
Products
The new substances formed in the reaction are
called products and written on the right side of
the equation.
e.g.
oxygen gas + glucose
Products
The new substances formed in the reaction are
called products and written on the right side of
the equation.
e.g.
oxygen gas + glucose
O2
+ C6H12O6
The two sides of the equation are separated by ?
The two sides of the equation are separated by an
arrow (pointing right) that is read as ?
The two sides of the equation are separated by an
arrow (pointing right) that is read as “produces”
or “yields.”
The two sides of the equation are separated by an
arrow (pointing right) that is read as “produces”
or “yields.”
e.g.
carbon dioxide + water
CO2
+ H2O
oxygen gas + glucose
O2
+ C6H12O6