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CHAPTER ONE

Chemistry studies/describes matter and energy.

Matter is anything that (1) occupies space and (2) has mass

mass = a measure of the amount of matter in an object

- one way to measure an object's mass is to measure the force it takes to accelerate an object (eg. it takes more force to accelerate a Cutlass than a STI, because the Cutlass has more mass); however, a more common way to determine the mass of an object is to use a balance to compare the object's mass with a standard mass

weight =/= mass

weight = the force that gravity exerts on an object --the force is directly proportional to the mass of the object; however, weight can change with the force of gravity, mass cannot

(a person may feel "weightless" in somewhere in outer space experiencing negligible external forces (gravitational or any other), but the person is never "mass-less")

- there are 3 states of matter commonly found on Earth: solid (shape and volume independent from its container/pressure), liquid (volume ~independent from its container/pressure; takes shape of its container), gas (takes shape and volume of its container/pressure)

another (4th) state of matter (that occurs naturally in the interiors of stars is): plasma -- also referred to as "ionizes gas(es)"

- "a plasma is a gaseous state of matter that contains appreciable numbers of electrically charged particles"

- plasma can also be observed in high-temp. environments on Earth: eg. plasma torches/CNC machines which use plasma to cut (not heat/melt) metal; there are also plasma T.V.s/screens, and neon/fluorescent lights and lightning strikes also serve as examples of plasma

- the presence of the positively charged particles (cations (+ free electrons)) found in a plasma imparts unique properties to the plasma --these unique properties justify their classification as a state of matter (distinct from gases, despite sharing properties such as taking the shape and volume of its container/pressure)

- plasma easily conducts electricity, and produces and responds to magnetic fields

- plasma is created when a gas is exposed to high temp. or high voltage electricity, causing its atoms electrons to knock into each other so fast/hard that they are ultimately knocked from their obit(s) leading to a mass or "soup" of free electrons

- samples of matter can appear to have properties of solids, liquids, and/or gases at the same time WHEN the sample is composed of many small pieces (eg. pouring sand like liquid because it is composed of many small grains of solid sand) AND matter can also have properties of more than one state WHEN it is a mixture (eg. clouds are a mixture of air (gas) and tiny particles of water (liquid/solid))

Chemistry is organized into 3 domains:

macroscopic domain - large enough to be observed by natural human senses (density, solubility, flammability, boiling, freezing)

microscopic domain - most often too small to be observed (and thus is mostly only imagined), however sometimes can be seen under a microscope or other similarly purposed instrument: biological cells, molecules (eg. H2O), atoms, ions, electrons, protons, neutrons, chemical bonds, etc.

symbolic domain - eg. periodic table of elements - chemical symbols, formulas and equations

the same symbols can represent different things in the macro and micro domains

law of conservation of matter

there is no detectable change in the total quantity of matter present when matter converts from one type to another (chemical change) OR changes among solid, liquid, or gaseous states (physical change)

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