Matter and Change

How do scientists define matter?

Matter is all the “stuff” that exists in the universe. Everything you can see and touch is made of matter, including you! The only things that don’t matter are forms of energy, such as light and sound. In science, the matter is defined as anything that has mass and volume.

What is mass? What is the basic SI unit of mass?

Mass is a measure of the amount of matter in a substance or an object. The basic SI unit for mass is the kilogram (kg), but smaller masses may be measured in grams (g).

What does volume measure? Name two different units that might be used to measure volume.

Volume is a measure of the amount of space that a substance or an object takes up. The basic SI unit for volume is the cubic meter (m3), but smaller volumes may be measured in cm3, and liquids may be measured in liters (L) or milliliters (mL).

Explain how to use the displacement method to find the volume of an irregularly shaped object.

You put water to a known volume and then add the object into it and see the new volume. Then you subtract the new volume from the original volume.

What are physical properties?

Physical properties of matter are properties that can be measured or observed without matter changing to an entirely different substance. Physical properties are typically things you can detect with your senses.

What are examples of physical properties?

For example, they may be things that you can see, hear, smell, or feel.

What is density?

Density is an important physical property of matter. It reflects how closely packed the particles of matter are. When particles are packed together more tightly, the matter has a greater density.

How do you calculate density?

mass/volume = density

Define state of matter.

States of matter are different phases in which any given type of matter can exist.

List four states of matter. Which states of matter are most common on Earth?

There are actually four well-known states of matter: solid, liquid, gas, and plasma.

Compare and contrast solids, liquids, and gasses.

A solid is a state of matter in which particles of matter are tightly packed together. Solids also have definite shape and volume. A liquid is a state of matter in which particles can slip past one another and take the shape of their container. Liquids have definite volume. Gas is a state of matter in which particles of matter can pull apart from each other and spread out. Gas does not have definite shape or volume.

Define change of state, and give an example.

A change of state occurs whenever matter changes from one state to another. Common states of matter on Earth are solid, liquid, and gas. Matter may change back and forth between any two of these states.

Identify processes that change matter to a liquid state.

Melting and condensation

Why must energy be absorbed to change a liquid to a gas?

Heat energy is absorbed to vaporize a liquid because molecules which are held together by intermolecular forces in the liquid are separated as the gas is formed.

What are chemical properties?

Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter.

What is reactivity?

Reactivity is the ability of matter to combine chemically with other substances. Some kinds of matter are extremely reactive; others are extremely unreactive

What is flammability?

Flammability is the ability of matter to burn. When matter burns, it combines with oxygen and changes to different substances.

What is a physical change?

A physical change is a change in one or more physical properties of matter without any change in chemical properties. In other words, matter doesn’t change into a different substance in a physical change.

What are examples of physical changes?

Some examples are: cutting paper, ice melting, and a tablet dissolving in water

Can you reverse a physical change and how?

When matter undergoes physical change, it doesn’t become a different substance. Therefore, physical changes are often easy to reverse. For example, when liquid water freezes to form ice, it can be changed back to liquid water by heating and melting the ice.

What happens in any chemical change?

matter changes into an entirely different substance with different chemical properties.

List three signs that a chemical change has occurred.

bubbles are released, there is a change of color, or an odor is produced

Give an example of a chemical change. Explain why you think it is a chemical change.

An example of matter changing color is a penny changing from reddish brown to greenish brown as it becomes tarnished. The color change indicates that a new chemical substance has been produced. Copper on the surface of the penny has combined with oxygen in the air to produce a different substance called copper oxide.

Why can chemical changes often not be reversed?

Because chemical changes produce new substances, they often cannot be undone. For example, you can’t change ashes from burning logs back into wood. Some chemical changes can be reversed, but only by other chemical changes.

Pure substances

made of one type of particle

mixtures

made of more than one type of matter

weight

the measure of the force of gravity acting on an object measured using a spring scale units- newton

Mass vs. Weight

Mass is always constant and weight changes when gravity changes.

Meniscus

The curvature of liquids in glass containers

what makes something float or sink

If the objects density is less than the waters

Crystalline solids

particles arranged in a regular repeating pattern

amorphous

no repeating pattern, more random

surface tension

a force that pulls particles at the exposed surface of a liquid toward other liquid particles

viscosity

a liquids resistance to flowing

pressure of gases

more particles moving faster= more pressure

plasma

state of matter that resembles gas but can conduct electricity and respond to magnetic fields

boiling

liquid changes to a gas within the liquid forming bubbles

sublimation

a change directly from the solid to the gaseous state without becoming liquid

deposition

process in which a gas changes directly into a solid

examples of chemical changes

soured milk, rusted car, camp fire, baked cookies

conservation of mass

mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations