Types of Changes Matter Undergoes

• All changes in matter are classified as either ...

physical changes,

chemical changes,

or

nuclear changes.

Types of Changes Matter Undergoes

a) Physical Changes (Physical Reactions):

NO CHANGES IN COMPOSITION

A change resulting in the rearrangement of existing particles in which no new substance

is produced.

The compositions and chemical properties of all reactants remain the same.

Physical reactions may be either endothermicor exothermic.

Types of Changes Matter Undergoes

• A physical change (reaction) is a change in which the composition of the reactant does NOT change.

H2O(s) H2O(l)

C12H22O11(s) H2O(s) C12H22O11(aq)

+

Types of Changes Matter Undergoes

i. Melting (Fusion) –

ENDO OR EXO? __________

ii. Freezing (Solidification) –

ENDO OR EXO? __________

iii. Boiling (Vaporization) –

ENDO OR EXO? __________

iv. Evaporation (Vaporization) –

ENDO OR EXO? __________

solid to liquid

liquid to solid

liquid to gas

liquid to gas

ENDO

ENDO

ENDO

EXO

Types of Changes Matter Undergoes

v. Condensation (Liquefaction) –

ENDO OR EXO? __________

vi. Sublimation (Vaporization) –

ENDO OR EXO? __________

vii. Deposition (Solidification) –

ENDO OR EXO? __________

ENDO

EXO

EXO

gas to liquid

solid directly to gas

gas directly to solid

Types of Changes Matter Undergoes

• Iodine (I2), dry ice (CO2), & naphthalene (C10H8) are three substances that will significantly sublime at room temperature.

Types of Changes Matter Undergoes

viii. Dissolution (Dissolving) –

ix. Crystallization –

x. Breaking –

xi. Magnetizing –

aqueous, gas to aqueous…solid to aqueous, liquid to

aqueous to solid

big to small

nonmagnetic to magnetic

Types of Changes Matter Undergoes

b) Chemical Changes (Chemical Reactions):

CHANGES IN COMPOSITION

A change in which something new is produced.

The composition and properties of all reactants change.

Chemical reactions MUST be either endothermicor exothermic!

Types of Changes Matter Undergoes

• A chemical change (reaction) is a change in which the composition of the reactant DOES change but the identity of the atoms involved do not change.

Fe(s) Fe3O4(s)

in O2

rust

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

(C6H12O6)n

in O2

C(s)

CO2(g) H2O(g)burn

Types of Changes Matter Undergoes

i. Combustion –

ii. Rusting –

iii. Neutralization –

iv. Fermentation –

v. Decomposition –

A reaction with oxygen in which lightand heat are produced. Burning!

A reaction between Fe and O2 in whichno noticeable light/heat are produced.

A reaction between an acid and abase that produces a salt and water.

A reaction in which sugar changedinto alcohol and carbon dioxide.

A reaction in which a substance isbroken into new smaller substances.

EXOTHERMIC!

Types of Changes Matter Undergoes

c) Nuclear Changes (Nuclear Reactions):

CHANGES IN COMPOSITION AND ELEMENTS

A reaction in which the nucleus of an atom is changed.

Nuclear reactions are always exothermic.

Nuclear reactions often produce new elements!

Types of Changes Matter Undergoes

• A nuclear change (reaction) is a change in which the composition of the reactant DOES change AND the nuclei of the atoms involved ALSO change.

1H 4He

235U 142Ba + 91Kr

Types of Changes Matter Undergoes

i. Fission –

A reaction in which a larger atom is splitinto two or more smaller atoms.

Nuclear power plants produce energy usingcontrolled fission reactions.

Types of Changes Matter Undergoes

235U 142Ba + 91Kr

ii. Fusion – A reation in which smaller atoms combineto produc larger atom.

Our sun produces energy by changing hydrogeninto helium through fusion!

Types of Changes Matter Undergoes

1H 4He