What is Chemistry?
Unit 1 – Introduction to Chemistry
What is Chemistry?
Chemistry is the study of matter
What is matter? Matter is anything that has mass and
volume
What is mass and volume?
Mass: The amount of matter in an object How much an object weighs
Volume: The amount of space an object occupies
Are mass and weight the same thing?
Balance Scale
Gravity independent Gravity dependent
Anywhere Changes with gravity
Now that we know what matter is…
Can you think of 5 examples of matter?
Can you think of the 4 examples of non-matter?
Brainstorm with your partner please.
Matter – further break down
What is the building block of matter? Atom – the basic unit of matter
What is it called when two or more atoms are combined? Molecule – two or more atoms that behave as a
unit They are chemically bonded
Classification of Matter (pg. 3)
Matter can be classified into two major groups: Pure Substance Mixture
Pure Substance
Definition: Made up of only one kind of atom or
molecule Example: carbon
Mixture
Definition: Matter that is made up of more than one
kind of atom or molecule. Two or more pure substances mixed Example: salt water
Not chemically bonded Can be separated by physical means
Further classification:
Pure substance and mixture can be further classified Pure substance can be further classified
into an element or compound Mixture can be further classified into a
homogeneous or heterogeneous mixture
Element
Definition: A pure substance that is made of only a
single kind of atom Cannot be broken down Found on periodic table Most basic form of matter
Example: Copper
Compound
Definition: A pure substance that is made of more
than one kind of atom 2 or more elements chmically bonded
Example: water
Homogeneous mixture
Definition: A mixture that has a uniform composition Example: Soda
Heterogeneous mixture
Definition: A mixture that is non-uniform
It has layers Example: muddy water
homework
Read 1-1 Answer ?s 1-10 on page 23 (write down
the question)
States of matter (page 3)
Also called the phases of matter
Solid Liquid Gas
Solid Has both a definite shape and definite
volume At the molecular level, the particles that
make up the solid are close together and many times are locked into a very regular framework called a crystal lattice The atoms and molecules are held tightly
in a rigid structure but vibrate slightly about their fixed positions
Cannot compress
Liquid Definite volume, but variable shape Cannot compress It conforms to the container in which it is
placed Particles in the liquid are not held together in
a rigid manner that is characteristic of solids However, the distances between the particles
are constant on average Particles are moving much more than in the
solid There are usually clumps of particles moving
relatively freely among other clumps
Gas
No fixed shape or volume Expand to fill any container they occupy The particles move rapidly with respect
to each other and act basically independently of each other
Plasma
Sea of ions Example: Sun
Changing phase
Solid
melting
freezing Sublimation Liquid
boiling
condensing Gas
Deposition
States of matter
Identified using the following: If an item is a solid, it is followed by (s)
Ice = H2O (s)
If an item is a liquid, it is followed by (l) Tap water = H2O (l)
If an item is a gas, it is followed by (g) Steam = H2O (g)
Methods of separating mixtures
Separate by physical means Substances are not altered chemically
Examples: filtration, evaporation, centrifuge, decant, chromatography, distillation, density
Identification of matter
Matter can be identified by two types of properties Physical Chemical
State Functions
Intensive property Any property of a system that does not depend on
how the process Density Specific heat
Extensive Property depends on amount of matter
VolumePressureTemperature Internal Energy
Physical properties
Can be observed without changing the composition of the matter
Appearance of physical state changes, but not the chemical composition shape Examples: color, volume, shape, mass,
length, odor, solubility, density, specific heat, melting point and boiling point
Chemical properties
Observed only when substances interact with one another
The original substance changes into something else
Different chemical substances are formed
Breaks chemical bonds
Examples of Chemical Properties
•Rust
•Burning
•Fruit ripening
•Baking
•Souring
Physical vs. Chemical Changes
Physical – original substance still exists Only the form or physical appearance changes
Example: cutting in half writing on paper changing the phase of matter
Physical vs. Chemical Changes
Chemical - produces one or more new substances Observed only when substances interact with
one another The original substance changes into
something else Example:
bubbles (production of a gas) change in color forms a precipitate (solid) produces heat or light (explosions)
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