8. Certain conditions are needed
for chemical change to happen.
These are the application of
or with a change in
and presence of oxygen. Paper,
wood, candle or any fuel can
decompose into ash. In the
process of combustion heat, fuel
and oxygen are needed to
9. Burning is impossible if any of
the factors is missing. The
process of combustion changes
the materials chemically. The
product of this cannot be
returned to its original form.
Some chemical in materials may
transformed into heat or light
and the remains in the process is
10. Read each question carefully. Write the letter of the
correct answer in your notebook.
1. Which of the
following
gasses is
needed in
combustion
process?
A.Carbon
B. Oxygen
C.Helium
11. Read each question carefully. Write the letter of the
correct answer in your notebook.
2. Which pair is
needed to for
chemical
change to
happen?
A. Heat and fuel
B. Heat and
carbon
C. Heat and
oxygen
12. Read each question carefully. Write the letter of the
correct answer in your notebook.
3. The remain
product in
the process
of burning
is______.
A.Water
B.Smoke
C.Ash
13. Answer the question briefly.
4-5. Is it easy to
control a
grassfire on
summer, when
there is a
presence of
blowing wind?
Why?
25. Guide Questions:
1. What happened to the
exposed parts of the
apple? potato? banana?
2. What causes the change
in color of exposed parts
of the potato? Apple?
Banana?
27. Remember , the presence or absence of oxygen
cause changes in the materials. Vitamin C acted
as antioxidant that prevents the apple to turn
brown in color. This way, the apple will keep its
good appearance. Now, you understand why
apple and eggplants turn brown or showed
discoloration when exposed to oxygen.
28.
29. What made the exposed
part of the fruit darkened
in color?
30. How does OXYGEN affects
chemical change in some
materials?
1. Presence of oxygen can
decompose fruits and spoil
food.
31. 2. Exposure of some sliced fruits
and vegetables to oxygen cause
then to turn brown or dark.
33. Vacuum packing it removes air from the package
prior to sealing. The intent of vacuum packing is
usually to remove oxygen from the container to
extend the shelf life of foods and, with flexible
package forms, to reduce the volume of the
contents and package
34. Since rust makes materials
break easily, these structures
are coated with paint to keep
oxygen from reacting directly
with it.
35. When fleshy fruits such as apples, pears,
peaches, and bananas are cut open and
exposed to the air, their insides will often
turn brown within minutes as a result of the
oxidation process. Although brown fruit is
still nutritious and safe to eat, sometimes
the color can appear unsightly and
unappetizing. However, there are several
natural ingredients you can use together to
prevent your fruit from turning brown.
36. How to keep fruits from turning
brown when sliced.
1. Using honey and water
30 seconds
37. How to keep fruits from turning
brown when sliced.
2. Using lemon juice and water.
5 mins
38. How to keep fruits from turning
brown when sliced.
3. Using salt and water
6 mins
42. Describe the changes
happened in each picture.
What changes will take place
when you chop a wood?
What changes will take place
when you burn the wood?
What will happen to the
burning process of the wood
if there is no oxygen?
44. 1. Living things are dependent
to oxygen for breathing.
Lack of oxygen to the brain
may result to nausea and
vomiting.
2. Without oxygen, Nature
cannot produce CO2, in this
case plants cannot make
their own food.
45. 3. Combustion is impossible
in the absence of oxygen
and in this condition we
cannot cook our food.
Editor's Notes
! For todays Most Essential Learning Competency, you are expected to
What do we need to roast a chicken?
Is there any change takes place after it was cooked?
Can we bring back the chicken to its original form?
What we call this kind of change?
What do you think is/are cause/s of such change?
