Chapter 1:Chemistry

Chapter 2: MATTER, CHANGE, & ENERGY

What is Chemistry?• Chemistry: the study of the composition of

substances & the changes they undergo.

• PURE vs. APPLIED Chemistry

• Pure Chemistry: knowledge is accumulated for its own sake. Water boils

• Applied Chemistry: knowledge is used in ways that either benefit or harm people or environment.Boiling water can be used to sterilize

PURE CHEMISTRY LEADS TO APPLIED CHEMISTRY

 5 TRADITIONAL AREAS OF STUDY in Chemistry:

1. Organic-study of substances that contain carbon 

2. Inorganic-study of substances without carbon 3. Analytical-study of the composition of

substances 4. Physical-study of theories & experiments that

describe the behaviors of chemicals 5. Biochemistry-study of the chemistry of living

organisms

What is the Scientific Method?The Scientific Method is an approach to the

solution of scientific problems.

The number of steps involved varies from reference to reference but in general there are 5

basic steps:

1.Observations2.Hypothesis

3.Experiments4.Theory

5.Scientific Law

BREAKDOWN OF THE 5 STEPS:Observation: Why does something happen?

Hypothesis: A proposed reason for what is observedExperiment: To prove or disprove the hypothesis

Theory: Thoroughly tested explanation of why experiments give certain results

1. Time Tested Concept2. Useful & dependable predictions about the natural world3. Can never be proved; new experiments can disprove it

4. Can be wrong & changedEX: Big Bang Theory 

Scientific Law: Summarizing statement of observed experimental facts

1.  Accepted as TRUE2.  Can be proven and proven and proven

3.  Often expressed by simple mathematical relationshipsEX: Sir Isaac Newton’s Law of Motion

What are the states of matter?Solid: matter that has definite shape & volume packed closely together

o can’t be compressed

Liquid: matter that has no definite shape but definite volume (flows)

o takes the shape of the container

Gas: matter that has no definite shape or volumeo expands without limits-free to move

Vapor—the gaseous state of a substance that is usually a liquid or solid at room temperature.

Plasma---4th state that exists at very high temperatures.

Physical & Chemical PropertiesPhysical Property: Can be observed or measured w/o

alternating the identity of the materialEX: color, solubility, hardness, density, b.p. & m.p.

Physical Change: Alters a substance w/o changing its composition

EX: cutting, freezing, melting, dissolving, & boilingUSUALLY REVERSIBLE

Chemical Property: The ability of a substance to undergo a change that alters its identity

EX: rot, rust decompose, ferment, corrode, & decayChemical Change or Reaction: Any change when one or more substances are converted into NEW substances

NOT EASILY REVERSIBLE

Reactants: Starting substances that undergo changeProducts: New substances that are produced

Indications of Chemical Reactions:

1.  Evolution of heat and light2.  Production of a gas

3.  Formation of a precipitate

Law of Conservation of MassMass in neither created nor

destroyedMass of Products = Mass of Reactants