Unit 1: Introduction to Chemistry

matter

anything having mass or volume

mass

the amount of matter in an object

weight

the pull of gravity on an object

volume

the space an object occupies

volume units

L, dm³, ml, cm³

volume unit conversions

1L=1dm³; 1mL=1cm³

states of matter

solid, liquid, gas

atom

the basic building block of matter

elements

contain only one type of atom

monatomic elements

elements consisting of “unbonded” identical atoms

e.g: Fe, Al, Cu, He

polyatomic elements

elements consisting of several identical atoms bonded together

e.g: P4, S8

diatomic elements

H2, O2, Br2, F2, I2, N2, Cl2

allotropes

different forms of the same element in the same state of matter

molecule

a neutral group of bonded atoms

elements may consist of…

…either molecules OR unbonded atoms

compounds

two or more different types of atoms

have properties that differ from those of their constituent elements

e.g: Na: explodes in water

Cl2: poisonous gas

all samples of a given compound…

…have the same composition by mass

Composition

What matter is made of

Properties

Describe matter; what it looks like, smells like, how it behaves

States of matter

Solid (molecules vibrating)

Liquid (molecules close together)

Gas (molecules far apart)

Changes in state

Energy put into a system (ex: ice becoming liquid/muddy)

Energy removed from a system(ex: energy is removed from healthy living matter, leaving no energy and rendering it dead matter)

Sublimation

Solid to gas

Melting

Solid to liquid

Boiling

Liquid to gas

Freezing

Liquid to solid

Condensation

Gas to liquid

Deposition

Gas to solid

(Pure) substances

Fixed composition and fixed properties

-single chemical formula

Element

One type of atom

Ex: Fe, N2, S8, U

compounds

2+ different atoms

Ex: H20, NaCl, HNO3

Mixture

2 or more substances mixed together

Varying composition and properties

Substance NOT chemically bonded; retain individual properties

Homogeneous mixture(solution)

Same composition and properties throughout; evenly mixed at particle level

ex: salt water, koolaid

Heterogeneous mixture

Different composition and properties in the same sample; unevenly mixed

Ex: tossed salad, Raisin Bran

Alloy

Homogeneous mixture of METALS

Ex: bronze (Cu + Sn)

pewter (Pb + Sn)

Brass (Cu + Zn)

Suspension

Settles over time

Ex: paint, snow globes

settlement is suspended