Changes in Materials

Multiple Choice

Newspaper

• useful

• harmful

Multiple Choice

Coconut OIl

• Useful

• harmful

Multiple Choice

Lemons

• Useful

• harmful

Multiple Choice

scissors

• useful

• harmful

Multiple Choice

Paint

• useful

• harmful

​Matter has two properties – physical and chemical. Both of these properties have effects on matter. However, this lesson will focus on one chemical property of matter. The presence or absence of oxygen has various effects on matter. Among these common ones that you readily see are combustion and rusting.

​Investigate changes that happen in materials under the following conditions:

a. presence or lack of oxygen

Directions: Identify the objects whether they are useful or not.

​Let’s investigate...

​

Go to the kitchen and ask your mother or anyone in the house to help you cut an eggplant or peel a sweet potato (camote). Observe what will happen to the color of the sliced eggplant or the peeled camote after a few minutes.

​Matter undergoes changes. This can either be physical or chemical change. Physical changes happen when material change its size, shape, or form. When the composition of the material is altered, chemical change occurs. The formation of a new product, formation of gas, release or absorption of heat and formation or precipitate are some evidences of chemical change. These changes, will help and give us idea how to anage and minimize waste materials in the environment.

Multiple Choice

A physical change...

• changes the physical properties of an object, but does not create a new substance.

• creates a new substance and cannot be undone.

Multiple Choice

A chemical change

• changes the physical properties of an object, but does not create a new substance.

• creates a new substance and cannot be undone.

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

Multiple Choice

Is this an example of a physical or chemical change?

• physical

• chemical

​➢ Oxygen comprises 21% of the air that surrounds us. It has effects on different materials. Some fruits like apple, turnips, mango, etc. and some root crops like sweet potato eggplant, etc. have enzymes which when combined with oxygen gives it brown color. This process is called oxidation.

​

​➢ The combination of materials with oxygen is called Oxidation.

​

​➢ Oxidation is an example of chemical change.

​If you cut open an apple, initially, its flesh looks fresh and appetizing.

​

However, after an hour or so it does not. The flesh starts going brown.

​

The inside of the apple turns brown because of oxidation. By exposing the inside of the apple to air, which contains oxygen, it oxidizes.

​

In other words, substances in the inside of the apple react to the oxygen and make it turn brown. We call this browning oxidation.

​

➢ Combustion refers to the process where substance burns in the presence of oxygen.

➢ The three things needed for combustion or burning to take place are oxygen, fuel, and heat.

​

➢ If one of these three is not present, then combustion will not occur

​

➢ Iron when combined with oxygen form rust.

​

➢ The amount of rust formed in an iron depends on the moisture and humidity of the surroundings.

​

​Many common substances can undergo combustion—for example, paper, cloth, and natural gas. Combustion begins when the substance reaches a temperature called its ignition point. At this temperature oxygen combines with the substance fast enough to produce a flame. Different substances have different ignition points

​A substance may reach its ignition point by being heated, struck by a spark, or exposed to strong light. For example, a hot match can raise the temperature of a piece of paper to its ignition point. A spark can do the same thing. So can sunlight that is focused through a magnifying glass.

​Very fast combustion can cause an explosion. This type of combustion happens in a bomb or a firecracker. During an explosion air heats up so fast that it expands and moves outward with great force.

Multiple Choice

Another term for burning is

• Fire triangle

• Magnesium oxide

• Combustion

• Bustion

Multiple Choice

In this chemical reaction, which is the product/s?

Magnesium + Oxygen --> Magnesium oxide

• magnesium

• magnesium and oxygen

• magnesium oxide

• oxygen

Multiple Choice

Three things that are needed for combustion are:

• oxygen, nitrogen and carbon dioxide

• fuel, oxygen and carbon dioxide

• fuel, heat and oxygen

• fuel, heat and carbon dioxide

Multiple Choice

What does a fuel need in order to burn?

• fuel

• electricity

• oxygen

• hydrogen

Multiple Choice

Which of the following defines oxidation?

• A chemical reaction where a substance gains oxygen.

• A chemical reaction where a substance loses oxygen.

• A chemical reaction where a substance loses a metal.

• A chemical reaction where a substance gains a metal.

Multiple Choice

The rusting of iron is an example of

• a reduction reaction.

• an oxidation reaction.

• a reaction of iron with water.

• a reaction that dissolves iron.

Multiple Choice

The following are the ways to prevent rusting, except one.

• Keep it clean and dry.

• Apply paint.

• Let it wet and moist.

Multiple Choice

What will happen if one element needed for combustion is not present?

• The fire will continue its flame.

• Combustion will not occur.

• Combustion will still take place.

Multiple Choice

When an apple is cut, the fleshy part of the fruit did not change its color.

• True

• False

Multiple Choice

The condition which are required for combustion to take place are:

• fuel

• heat

• oxygen

• all of these