Chemistry of Materials Review

Chemistry of Materials Review

Test review

Multiple Choice

What is the smallest?

• an atom

• a molecule

• a speck of dust

• a copound

Multiple Select

What are examples of elements?

• CO₂

• Ca

• H

• O

Elements

Elements are the simplest pure substances made out of only one type of atom. Examples: Oxygen, Carbon, Hydrogen, Sodium, Iron, Etc.

Multiple Select

What are examples of compounds? (check all that apply)

• water (H₂O)

• Oxygen (O₂)

• Iron (Fe)

• Carbon Dioxyde (CO₂)

Compounds

• A compounds is a substance made from more than one element and joined by a chemical bond

• Examples of Compounds: water, salt, carbon dioxide, methane

Molecules and extended structures

• a molecule has a set number of each kind of atom

• an extended structure, however, can have varied numbers of each kind of atom bonded together to form a very large structure

• The structure of the particles in a substance determines its properties and the ways that the substance can be used.

Multiple Choice

What is an example of extended structure?

• sulfur

• diamond

• water

• ethane molecule

Material’s Properties and its Uses

• materials are made from a limited number of elements

• each element has characteristic properties such as color, solubility, density, and melting and boiling point

• properties of materials are used to identify materials and to determine appropriate uses for materials

Physical and Chemical Properties

• Physical properties are observed, measured, or calculated and do not involve reactions with another material

• Example of physical property: a substance’s density can be calculated: DENSITY = mass / volume

• Chemical properties describe the reaction of the material with another material

• Example of chemical property: reactivity with an acid or oxygen

Multiple Select

Which of the following are examples of physical properties? (check all that apply)

• density

• malleability

• reactivity to oxygen

• texture

Multiple Choice

Which of the following is an example of chemical property?

• density

• texture

• malleability

• reactivity to acid

Why Do Materials Have Unique Properties?

• Substances have specific structures based on what elements they are made of and how those elements bond together

• structures can be modeled to help explain the properties of materials, such as density and solubility

• some substances form small structures with only a few atoms bonded together

• other substances form larger structures with many atoms bonded together to form large molecules or extended structures

States of Matter

• Substances mostly exist in one of three different states—solid, liquid, or gas

• Particle models help explain the differences between these states. These models can show the distance between particles, particle motion (kinetic energy), and particle interactions

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As you add or remove thermal energy, a material might change state. During the melting and boiling points the temperature until the particle's interactions change to a new state

States of Matter

• Solids tend to have less particle motion and less distance between particles

• Gases tend to have more particle motion and more distance between particles

• Particles in liquids tend to be intermediate in motion and are almost as closely packed as in solids

States of Matter and Thermal Energy

• Adding thermal energy either increases the temperature and kinetic energy of particles or causes a phase change from solid to liquid or liquid to gas

• Removing thermal energy either decreases particles’ temperature and kinetic energy or causes a state change from gas to liquid or liquid to solid

• Transfer of thermal energy to a substance increases the substance’s average kinetic energy except during a state change

Multiple Choice

In which state of matter are the particles the farthest apart?

• solid

• liquid

• gas

Materials and Society

• Some large molecules and structures are made of small, repeating subunits (monomers)

• Hundreds to thousands of these monomers can bond together to form polymers, such as different types of plastics

• Some polymer chains can connect to form cross-linked polymers

•  Polymers have also allowed scientists and engineers to determine the limitations of technologies and how to adapt them for individual and societal needs, desires, and values

• Materials scientists and engineers consider specific properties when determining the best material for a product

• There are benefits and trade-offs to using all materials, including plastics

• Plastics, and other synthetic materials, are made from natural resources and have many impacts, both positive and negative, on human health and the environment

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Poll

How ready do you feel for the test tomorrow?

• I am ready!

• I just need a little more studying

• I have a lot of studying to do

• I am lost