Properties of Matter

Properties of Matter

Middle School

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Learning Objectives

• Describe the atomic composition of simple molecules and larger extended structures.

• Analyze properties of substances to determine if a chemical reaction has occurred.

• Differentiate between the physical and chemical properties of matter.

• Explain how to measure and calculate mass, volume, and density.

Key Vocabulary

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Atom

An atom is the smallest and most basic unit that makes up a chemical element.

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Molecule

A molecule is formed when two or more atoms are chemically bonded together to form a substance.

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Extended Structure

Extended structures are large systems made of repeating subunits, such as in a crystal lattice.

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Chemical Reaction

A chemical reaction is a process that involves rearranging the atoms of substances to form new ones.

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Physical Property

This is a characteristic of a substance that can be observed without changing its chemical identity.

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Chemical Property

This is a property of a substance that becomes evident during or after a chemical reaction.

Key Vocabulary

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Mass

Mass is the measure of how much matter is packed into an object or substance.

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Volume

Volume describes the total amount of three-dimensional space that a substance or an object occupies.

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Density

Density is a measure of how much mass is contained in a given unit of volume.

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Solubility

Solubility is the special ability of a solid, liquid, or gas to dissolve in a solvent.

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Flammability

Flammability describes how easily and quickly a substance can ignite and burn when exposed to heat.

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Odor

Odor is the distinctive smell that is released by a particular substance, which can be pleasant or unpleasant.

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What are Atoms and Molecules?

• All substances are made of very tiny particles called atoms.

• Atoms are the basic building blocks of all matter.

• They combine with one another to form larger particles called molecules.

• The arrangement of atoms determines the properties of different substances.

Multiple Choice

What are the basic and most fundamental units of all matter?

• Atoms

• Molecules

• Substances

• Models

Multiple Choice

What is the relationship between an atom and a molecule?

• Molecules are formed when two or more atoms are joined together.

• Atoms are formed when two or more molecules are joined together.

• Molecules are the small particles that make up a single atom.

• Atoms and molecules are different words for the same particle.

Multiple Choice

If two different substances are made from the exact same types of atoms, what best explains why they have completely different properties?

• The way the atoms are arranged is different in each substance.

• One substance must have been made with larger atoms.

• The atoms in one substance are much older than in the other.

• One substance was visualized with a model and the other was not.

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How Atoms Are Organized: Structures

Simple Molecules

• ​Some substances are made of individual molecules that are not strongly connected to each other.

• ​​These types of arrangements are commonly found in everyday liquids, like water, and various gases.

• ​The molecules in these substances, such as oxygen, can move around freely and independently.

Extended Structures

• ​Other substances are formed from atoms or ions arranged in large, repeating, organized patterns.

• ​​These rigid network structures are typically found in solid materials like salt or diamonds.

• ​This underlying atomic structure determines the substance's properties, such as hardness and melting point.

Multiple Choice

What is the primary difference between how atoms are organized in simple molecules versus extended structures?

• One describes freely moving molecules, while the other describes a rigid, repeating pattern.

• One is found only in solids, while the other is found only in gases.

• One is made of large atoms, while the other is made of small atoms.

• One is made of ions, while the other is made of molecules.

Multiple Choice

Why are substances made of simple molecules, such as water and oxygen, typically found as liquids and gases?

• Because they are always made of very small atoms.

• Because their individual molecules are not strongly connected to each other.

• Because their atoms form large, rigid network structures.

• Because they are only found in materials like salt and diamonds.

Multiple Choice

A scientist discovers a new material that is extremely hard and has a very high melting point. Based on this information, what is the most likely conclusion about its internal structure?

• Its atoms are arranged in a large, organized, and repeating pattern.

• It is made of individual molecules that can move around freely.

• Its properties are not determined by its atomic structure.

• It is most likely a liquid at room temperature.

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Physical Properties: Mass and Volume

Mass

• Mass is the amount of matter that makes up a substance or an object.

• ​​It is a size-dependent property, meaning it changes with the size of the object.

• ​It is measured using a balance and is different from weight, which involves gravity.

Volume

• ​Volume is the total amount of space that a substance or an object occupies.

• ​​It is also a size-dependent property, so a larger object has a greater volume.

• ​Its value is measured with a graduated cylinder or by using a mathematical formula.

Multiple Choice

What is the primary difference between mass and volume?

• Mass is the amount of matter in an object, while volume is the amount of space it occupies.

• Mass is measured with a graduated cylinder, while volume is measured with a balance.

• Mass depends on gravity, while volume is a measure of an object's size.

• Mass changes with an object's location, while volume remains constant.

Multiple Choice

If a student cuts a large block of clay into a smaller piece, they will find that both its mass and volume have decreased. Why does this happen?

• Both properties are size-dependent, so changing the object's size changes both its mass and volume.

• The tools used to measure mass and volume are the same.

• Mass and volume are only present in objects that are large in size.

• Cutting the clay in half increases the force of gravity on it.

Multiple Choice

Which of the following statements correctly matches the measurement tool with the property?

• Mass is measured with a graduated cylinder; volume is measured with a balance.

• Mass is measured with a balance; volume is measured with a graduated cylinder or formula.

• Both mass and volume are measured with a balance.

• Both mass and volume are measured with a graduated cylinder.

Understanding Density

Multiple Choice

What does the density of a substance describe?

• How tightly matter is packed into a specific volume.

• The total weight of an object on a scale.

• The amount of space an object occupies.

• The shape and texture of a substance.

Multiple Choice

What is the correct method to calculate the density of an object?

• By dividing the object's mass by its volume.

• By multiplying the object's mass by its volume.

• By dividing the object's volume by its mass.

• By adding the object's mass and volume together.

Multiple Choice

If a large gold nugget is cut into two smaller pieces, what can be concluded about the density of each piece?

• The density of both pieces is the same.

• The smaller piece has a greater density.

• The larger piece has a greater density.

• The density of both pieces is now zero.

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Chemical Properties and Reactions

• A chemical property describes how a substance reacts, creating a new substance.

• ​In a reaction, atoms regroup to form new substances with different properties.

• For example, flammable steel wool reacts to form a new non-flammable powder.

• Signs of a reaction include changes in flammability, odor, or solubility.

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Multiple Choice

What is a chemical property?

• A property that describes how a substance reacts to create a new substance.

• A property that can be observed without changing the substance.

• A property related to the size or shape of a substance.

• A property that describes the color or texture of a substance.

Multiple Choice

What happens to the atoms of a substance during a chemical reaction?

• The atoms of the original substance are destroyed.

• The atoms of the original substance regroup to form new substances.

• The substance changes its state, but its atoms stay the same.

• The properties of the substance change, but the atoms do not.

Multiple Choice

Flammable steel wool is burned and turns into a powder that is no longer flammable. What conclusion is best supported by this observation?

• A chemical reaction occurred because a new, non-flammable substance was formed.

• Only a physical change occurred because the steel wool changed color.

• The steel wool melted, which is not a sign of a chemical reaction.

• No reaction happened because the total number of atoms stayed the same.

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More Properties for Identification

• Scientists use a combination of properties to identify substances.

• ​Conductivity is the ability to transfer electricity or thermal energy.

• Melting and boiling points are unique temperatures for state changes.

• Solubility is the ability of a substance to dissolve in another.

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Multiple Choice

What is the primary reason scientists use a combination of a substance's properties?

• To identify the substance

• To change the substance's state

• To increase the substance's mass

• To create a new substance

Multiple Choice

A material that allows electricity to pass through it easily has which property?

• High conductivity

• Low solubility

• A high melting point

• A low boiling point

Multiple Choice

A student confirms that an unknown liquid is soluble in water. What would be the best next step to help identify the liquid?

• Measure the temperature at which it boils

• Pour it into a larger container

• See if it dissolves another substance

• Observe its color more closely

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Common Misconceptions

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Summary

Poll

On a scale of 1-4, how confident are you about identifying substances using their properties?

• 1

• 2

• 3

• 4