3. Combustion It is a chemical change
that produces heat
and light through
burning.
Three elements are
needed for
combustion-fuel, heat
and oxygen.
Heat ignites the fuel.
Oxygen in the air reacts
with the fuel to release
heat and light.
Combustion will stop if.
a. Oxygen is not present.
b. Fuel runs out.
4. Oxidation
It is a chemical change that
happens when oxygen with
the chemical composition
of a material.
Examples:
1. color change of some
fruits, vegetables, and root
crops when cut open.
2. formation of rust in iron
5. Mixing of acids
and bases.
An ACID is a compound
that separates into
hydrogen ions when
added to water.
A BASE is a substance
that can get or take a
hydrogen ion when
contained with another
substance.
7. Decomposition
Decomposition or spoilage, is a type of chemical
change in which the components of matter are slowly
broken down into smaller forms and eventually
deteriorate or become decayed.
8. Review 1
Which of the following is a chemical
change?
A. melting of ice
B. dry ice turning into carbon dioxide gas
C. denting of metal
D. Burning of wood
9. Review 2
Which of the following statements is true?
A. Chemical changes are changes that affect
the composition of matter, and a new
product is formed.
B. Rusting of metal is a physical change.
C. Physical changes are changes that affect
the composition of matter, and a new
product is formed.
D. Deposition is a chemical change.
10. Review 3
Which of the following is an important
part of combustion?
A. water
B. metal
C. magnet
D. oxygen
11. Review 4
Which of the following will happen if the
jars will be tightly closed?
A. The oxygen will ran out and the fire will
burning.
B. The oxygen will ran out and the fire will
ran out too.
C. The candle will explode.
D. The jar will be melted.
12. Review 5
Which of the following causes iron to rust?
A. carbon dioxide
B. oil and water
C. Salt and pepper
D. water and oxygen
13. Review 6
____________ is a compound that
separates into hydrogen ions when added
to water.An example of this is vinegar.
A. base
B. salt
C. acid
D. oxygen
14. Review 7
Which of the following is produced when
acid and base react with each other?
A. salt and water
B. oxygen and iron
C. more acid
D. more base
15. Review 8
_______________ is a type of chemical
change in which the components of matter
are slowly broken down into smaller forms.
A. deposition
B. decomposition
C. filtration
D. distillation
16. Review 9
Which of the following helps oxygen react
with iron to form rust?
A. oil
B. water
C. paint
D. plastic
17. Review 10
Which of the following energy is produced
during combustion?
A. Light and Heat
B. Light and Electricity
C. Heat and Electricity
D. Chemical and Electricity
