Chemistry Notes
Chemistry –the study of matter and its changes
Matter – anything that has mass and takes up space
I.
History of Chemistry
A. Philosophers
1. 1st theories came from China, India, and
Greece
2. explained that all things are made up of
basic substances
B. Alchemy/Alchemists
1. one of the earliest forms of chemistry
2. tried to find philosopher’s stone which
could change metal into gold
3. tried to produce the elixir of life which
could give unending life
C. Physicians
1. Van Helmont –Belgian chemist/doctor
a. thought air and water were the only
elements
b. invented the word gas and studied
gasses
2. Robert Boyle –(Ireland) 1st true chemist
a. taught that theories have to be
supported by EXPERIMENTS
b. believed that matter was made up of
atoms
II. States of Matter
Matter –anything that takes up space and has mass
A. There are three states (forms)
Solid
Liquid
Shape
Keeps its
Takes the
shape
shape of its
container
Volume
Keeps its
Keeps its
Amnt. of
volume
volume
space it
takes up
Energy
Molecules
Little energy More energy
than a solid
of matter
Gas
Takes the
shape of its
container
Takes the
volume of its
container
Has a lot of
energy
B. Matter has 2 types of properties
1. physical –properties that can be observed
without changing the make-up or identity
of the matter
ex. density, boiling point, melting point,
electrical conductivity, solubility
2. chemical –describe matter based on its
ability to change into a new kind of
matter.
Ex. flammability, rusting, reactivity with
acid or water
C. Matter can change in two ways
1.Physical change –to change the physical
properties of matter (can usually be undone)
a. melting –solid changes to a liquid
(increased energy)
b. vaporization –liquid changes to a gas
(increased energy)
c. freezing –liquid changed to a solid
(decreased energy)
d. condensation –gas changes to a liquid
(decreased energy)
2.Chemical change –to change the chemical
properties of matter to make a new
substance (usually cannot be undone)
III. ATOMS
A. Definition: the smallest particle of an element
B. Parts of an atom
1. nucleus –central part of an atom, contains
protons and neutrons
2. protons –positively charged particles,
found in the nucleus
3. neutrons –neutrally charged particles,
found in the nucleus
4. electrons –negatively charged particles,
found orbiting the nucleus
(REMEMBER –the # of protons = # of
electrons)
C. Diagram of an atom
(-)
electron
orbit/shell
neutron
nucleus
proton
(+)
IV. Elements
A. Definition: a substance made up of only one
kind of atom
B. Reading the Periodic Table
1. there are 92 naturally occurring elements
2. elements are organized on a periodic
table (first made by Mendeleev)
3. chemical symbol –one or two letters used
to represent an element’s name (the first
is always capitalized) ex. Ca =calcium
4. atomic mass –the average mass of one
atom of that element (protons+ neutrons)
5. atomic number –the number of protons in
an atom of that element, equal to the
number of electrons in that element
V.
Compounds
A. Definition: when two or more elements are
chemically joined
B. molecules are the simplest part of a compound
C. compounds have different properties than the
elements which make them up
D. elements in a compound can be chemically
joined in two ways
1. ionic bond –one or more electrons from
one atom are transferred to another
atom
2. covalent bond –atoms share one or more
electrons
E. Acids and Bases are types of compounds
1. Acids
-produce hydrogen ions
-taste sour
-turn blue litmus paper red
2. Bases
-produce hydroxide ions
-taste bitter
-turn red litmus paper blue
VI.
Mixtures and Solutions (physically joined not
chemically)
A. Mixtures
1. held together by physical forces
2. examples –concrete, trail mix, water and
sand
B. Solutions
1. held together by physical forces
2. mixed up molecules have an even
distribution
3. examples –sugar water, lemonade