Chapter 1.1: Some Fundamental Definitions

Flashcards from Chapter 1.1 of Chemistry: The Molecular Nature of Matter and Change.

Chemistry

The scientific study of matter and its properties, the changes it undergoes, and the energy associated with it

Matter

Anything that has mass and volume

Composition

The types and amounts of simple substances that make matter up

Substance

Matter with a defined, fixed composition, regardless of state

States of matter

Includes:

• Solid

• Liquid

• Gas

Solid

A state of matter that has a fixed shape that doesn’t conform to the container

• Particles lie next to each other in an array

Liquid

A state of matter that conforms to the container shape and has a surface constrained by volume

Gas

A state of matter with varying, conformant shape, filling the entire container but with no fixed surface

• Particles move randomly and with greater distance

Array

The three-dimensional arrangement of particles in solid matter

Properties

The characteristics that give each substance its unique identity

Physical properties

Characteristics a substance shows by itself

• Density

• Color

• Melting point

Chemical properties

Characteristics a substance shows as it changes into or interacts with another substance

Includes:

• Flammability

• Corrosiveness

• Acid reactivity

Physical change

A change that occurs when a substasnce alters its physical properties, not composition

• Water state changes still retain water structure

• Is more easily reversible, changing to different states easily

Chemical change

A change that occurs when substances change identity with different composition and properties

• Electrical currents can induce this in water, breaking apart bonds

• Not as reversible, requiring another one of these

Energy

The ability to do work

• Typically involves movement to transfer this to and from matter

• Is the sum of its potential and kinetic parts

Potential energy

Energy due to the position of the object relative to other objects

• Seen with a weight being raised above the ground, or the pulling apart of a spring

• In chemistry, this can be seen when two like charges come close together or two opposite charges diverge

Kinetic energy

Energy due to the motion of the object

• Seen with dropping the weight to the ground, or allowing a spring to relax

• In chemistry, this can be seen in gasoline powering an engine to convert chemical-based potential energy into kinetic energy

Principles of energy

Includes:

1. Conservation of energy (energy is neither created nor destroyed)

2. Lower energy states are more stable than higher states

Conservation of energy

The principle of energy that energy is neither created nor destroyed

Lower-energy states

These are more stable than higher-energy states