CH.3 States and Properties of Matter
Basic Chemistry - Chapter 3: Matter and Energy
3.2 States and Properties of Matter
Learning Goal: Identify the states and the physical and chemical properties of matter.
States of Matter - Solids (1 of 2)
Matter on Earth exists in one of three physical states: solid, liquid, or gas.
Characteristics of Solids:
Solids have a definite shape and a definite volume.
Example: Amethyst, a solid, is a purple form of quartz, represented by its chemical formula, SiO2.
States of Matter - Solids (2 of 2)
In solids, particles have distinct features:
Held together by strong attractive forces.
Arranged in a rigid manner.
Can only move by vibrating slowly in fixed positions.
States of Matter - Liquids
Liquids possess unique attributes:
Have a definite volume, but not a definite shape.
Contain particles that exhibit slow movement in random directions.
Liquids maintain their volume but take the shape of their container.
States of Matter - Gases
Gases are characterized by the following:
Do not have a definite volume or a definite shape.
Contain particles that are placed far apart, move at high speeds, and have little attraction to each other.
Gases conform to both the shape and volume of their container.
Physical States of Matter Table 3.1 - A Comparison of Solids, Liquids, and Gases
Characteristic | Solid | Liquid | Gas |
|---|---|---|---|
Shape | Has a definite shape | Takes the shape of the container | Takes the shape of the container |
Volume | Has a definite volume | Has a definite volume | Fills the volume of the container |
Arrangement of Particles | Fixed, very close | Random, close | Random, far apart |
Interaction Between Particles | Very strong | Strong | Essentially none |
Movement of Particles | Vibrate in fixed positions | Move slowly around each other | Move rapidly, spread out |
Examples | Ice, salt, iron | Water, oil, vinegar | Water vapor, helium, air |
Physical Properties
Definition: Physical properties can be observed or measured without affecting the identity of a substance.
Examples Include:
Shape
Color
Melting point
Boiling point
Physical state of a substance.
Example Characteristics of a Penny:
Round shape
Orange-red color (due to copper)
Solid state
Shiny luster.
Table 3.2 - Some Physical Properties of Copper:
Property
Value
State at 25 °Celsius
Solid
Color
Orange-red
Odor
Odorless
Melting Point
1083 °Celsius
Boiling Point
2567 °Celsius
Luster
Shiny
Conduction of Electricity
Excellent
Conduction of Heat
Excellent
Physical Changes
Definition: Physical changes occur when matter undergoes a physical change of state, but its composition remains constant.
Example: Water can exist in three states:
Ice
Water
Steam.
Compounds Contain Elements
Definition of a compound: A compound consists of two or more elements that are chemically bonded together.
Example: Table salt is a compound that includes the elements sodium and chlorine.
The decomposition of salt (NaCl) yields sodium and chlorine elements.
Key Concept: Elements cannot be broken down further.
Chemical Properties
Definition: Chemical properties describe the capacity of a substance to interact with other substances and undergo changes to form a new substance.
Example of Chemical Change: When sugar is heated, it transforms and creates a caramelized topping for flan.
Chemical Changes
Definition: Chemical changes occur when the original substance is converted into a new substance with different physical and chemical properties.
Example: When iron nails corrode in the presence of water, they form a new substance - a red-orange powder known as rust (Fe2O3).
Examples of Physical and Chemical Properties and Changes
Table 3.3 - Summary of Physical and Chemical Properties and Changes
Physical Property: A characteristic of a substance, such as color, shape, odor, luster, size, melting point, or density.
Chemical Property: A characteristic that indicates the ability of a substance to form another substance, e.g., when paper burns, or iron rusts, silver tarnishes.
Change in Physical Property: Maintains the identity of the substance.
This can include changes of state, size, or shape.
Change in Chemical Property: Indicates a conversion to new substances, e.g., paper burns to form ash, gases, and heat.
Physical and Chemical Changes
Table 3.4 - Examples of Some Physical and Chemical Changes
Physical Changes:
Water boils to form water vapor.
Paper is cut into tiny pieces.
Sugar dissolves in water to produce a sugar solution.
Iron has a melting point of 1538 °Celsius.
Chemical Changes:
Water and cesium combine explosively.
Paper ignites and produces heat, ashes, carbon dioxide, and water vapor.
Heating sugar forms a smooth, caramel-colored substance.
Iron combines with oxygen to produce orange-red iron oxide (rust).
Sample Problem: Classifying Changes
Classify each of the following as a physical or chemical change:
a. A gold ingot is hammered to form gold leaf.
b. Gasoline burns in air.
c. Garlic is chopped into small pieces.
d. Milk left in a warm room turns sour.
e. A mixture of oil and water is separated.
Solution to Sample Problem
a. Physical change
b. Chemical change
c. Physical change
d. Chemical change
e. Physical change
3.2 States and Properties of Matter Review
Learning Goal: Identify the states and the physical and chemical properties of matter.
The three states of matter are:
Solid
Liquid
Gas
A physical property is defined as a characteristic of a substance that can be observed or measured without affecting the identity of the substance.
A physical change occurs when physical properties change, but the composition of the substance remains unchanged.
A chemical property signifies a substance's potential to change into another substance.
A chemical change occurs when one or more substances react, resulting in a new substance with different physical and chemical properties.