Chapter 2 *Physical Science Honors Study Guide

The temperature at which a substance changes from solid to ________________________________ is its melting point.

liquid

Nitrogen has an extremely ___________ reactivity

low

A ________________________________ ___________________________ occurs when some of the properties of a material change, but the substances in the material remain the same.

physical change

Flammability and reactivity are two examples of _____________ properties.

chemical

An ___________________ is a substance that cannot be broken down into simpler substances.

element

Substances can be classified into two categories— ________________ and ___________________.

elements and compounds

Scientists follow these steps in using properties to identify a material:

Decide which properties to test. Do tests on a sample of the unknown. Compare the results with the data reported for known materials

__________________________________ is the ratio of the mass of a substance to its volume.

Density

_____________________________ is the hardest known material.

Diamond

___________________________ is a process that separates substances in a solution based on their boiling points.

Distillation

_______________________________ is a process that separates materials based on the size of their particles.

Filtration

______________ is a material's ability to burn in the presence of oxygen.

Flammability

_____________________________ is the ability of a solid to be hammered without shattering.

Malleability

_________________ reacts easily with most other elements.

Oxygen

______________________ is the property that describes how readily a substance combines chemically with other substances.

Reactivity

_________________________ is the tendency of a liquid to keep from flowing.

Viscosity

An ____________ is the smallest particle of an element.

atom

Solids that shatter when struck are _______________________.

brittle

Mixtures can be classified how?

by how well the parts of the mixture are distributed throughout the mixture.

Even if you observe a color change, a gas, or a precipitate, you _________________ be sure a chemical change has taken place.

cannot

C represents what?

carbon

Properties _______________ when elements join and form compounds.

change

When matter undergoes a chemical change, the composition of the matter ___________________________.

changes

A _________________________ ________________________ is any ability to produce a change in the composition of matter.

chemical property

Each of these changes is a ________________ that a chemical change has produced at least one new substance.

clue

A __________________________ contains some particles that are intermediate in size between the small particles in a solution and the larger particles in a suspension.

colloid

Every sample of a given substance has the same properties because a substance has a fixed, uniform _______________________.

composition

A ____________________ is a substance that is made from two or more simpler substances and can be broken down into those simpler substances.

compound

A material's ability for allowing heat to flow through it is called ______________________________.

conductivity

Materials that have high conductivity, such as metals, are called ___________________.

conductors

The properties of a compound _________________ from those of the substances it is made from.

differ

If ________________________ substances are present after the change takes place, then the change is chemical, not physical.

different

It is not always __________________ to tell a chemical change from a physical change.

easy

An element has a _________________ composition because it contains only one type of atom.

fixed

Au represents what?

gold

The _____________________ of two materials can be compared by seeing which of the materials can scratch the other.

hardness

A suspension is a _______________________________ mixture that separates into layers over time.

heterogeneous

In a _________________ mixture, the parts of the mixture are noticeably different from one another.

heterogeneous

Oxygen is a __________________ reactive element

highly

In a _______________________ mixture, the substances are so evenly distributed that it is difficult to tell one substance in the mixture from another.

homogeneous

Knowing the physical properties of matter can be useful in the following ways:

identifying a material, choosing a material for a specific purpose, and separating the substances in a mixture.

A rusty chain or bolt is more likely to break than a new chain or bolt, because rust is weaker than _________________________.

iron

Rust forms when oxygen reacts with ___________________ and ___________________.

iron and water

The temperature at which a substance boils is its boiling point. What does it do?

it changes liquid to gas

A mixture can be classified as a solution, a suspension, or a colloid. This classification is based on the size of a mixture's _________________ particles.

largest

Properties determine which ______________________________ are chosen for which uses.

materials

Chemical properties can be observed only when the substances in a sample of ______________________ are changing into different substances.

matter

Most ________________ are malleable.

metals

A chemical change occurs when a substance reacts and forms one or more ___________ substances.

new

A homogeneous mixture appears to contain only _______ substance.

one

Some _____________________ __________________ can be reversed, and some cannot be reverse

physical changes

Viscosity, conductivity, malleability, hardness, melting point, boiling point, and density are examples of ________________________ _______________________________.

physical properties

A _____________________ ________________________ is any characteristic of a material that can be observed or measured without changing the composition of the substances in the material.

physical property

If different substances are not _____________________, then the change is physical, not chemical.

present

A compound always contains two or more elements joined in a fixed _____________________.

proportion

Matter that always has exactly the same composition, or makeup, is classified as a ___________ _________________, or simply a substance.

pure substance

Density can be used to test the ______________________ of a substance.

purity

No two elements have the ____________ type of atom.

same

When matter undergoes a physical change, the composition of the matter remains the __________________________.

same

Some properties can be used to ____________________________ mixtures.

separate

Filtration and distillation are two common __________________________ methods.

separation

The greater the viscosity, the _______________________ the liquid moves.

slower

At room temperature, most elements are ___________________.

solid

A _________________________ forms when substances dissolve and form a homogeneous mixture.

solution

The properties of a mixture are less uniform than the properties of a _______________________.

substance

Chemists use ______________ to represent elements.

symbols

Thick liquids have a high viscosity; therefore...

thick liquids have a high viscosity, and thin liquids have a low viscosity.

The properties of a mixture can __________ because the composition of a mixture is not fixed.

vary

In ___________________, there are always two hydrogen atoms for each oxygen atom

water

Three common types of evidence for a chemical change are...

• change in color, • the production of a gas, • the formation of a precipitate, or a solid that separates from a liquid mixture.