1.4, 1.5 Physical and Chemical Changes/Properties, Energy: A Fundamental Part of Physical and Chemical Change

1.4 Physical and Chemical Changes and Physical and Chemical Properties 1.5 Energy: A Fundamental Part of Physical and Chemical Change

physical changes

changes that alter only state or appearance, but not composition; atoms/molecules that compose a substance do not change their identity (e.g. water boiling, dissolving)

chemical changes

changes that alter the composition of matter; atoms rearrange, transforming original substances into different substances (e.g. rusting iron)

physical property

a property that a substance displays without changing its composition (e.g. odor, taste, color, appearance, melting point, boiling point, volatility, density, solubility)

chemical property

a property that a substance displays only by changing its composition via a chemical change (e.g. corrosiveness, flammability, acidity, toxicity, etc.)

chemical

Only ________(physical/chemical) examination can confirm whether a particular change is physical or chemical.

typically physical changes

changes in state of matter (e.g. melting or boiling), changes in physical condition of matter (e.g. cutting or crushing)

typically chemical changes

changes involving chemical reaction, often evidenced by temperature or color changes

energy

physical and chemical changes are usually accompanied by _______ changes

energy

the capacity to do work

work

the action of a force through a distance

kinetic energy

the energy associated with an object’s motion

potential energy

the energy associated with an object’s position or composition

total

the _____ energy of an object is a sum of its kinetic energy and its potential energy

thermal energy

energy associated with temperature of an object, form of kinetic energy associated with the motion of individual atoms or molecules that make up an object

law of conservation of energy

a law stating that energy can neither be created nor destroyed, only converted from one form to another; although it can flow from one object to another, the total quantity of energy remain constant

decreases

systems with high potential energy tend to change in a way that _________(increases/decreases) their potential energy

high

objects/systems with ____ (high/low) potential energy tend to be unstable)

less

the molecules that result from a chemical change harnessed to do work have ____ (more/less) potential energy than the original molecules

chemical potential energy

primarily arises from electrostatic forces between electrically charged particles that compose atoms and molecules