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.