Transcript PowerPoint

Chapter 1
Chemistry: What is Chemistry
(A whole lot of fun!)
Objectives
•
•
•
•
•
Describe chemistry
Classify and describe the types of matter
Describe physical and chemical properties
Describe physical and chemical changes
Recognize clues a chemical change has
occurred
What is Chemistry?
• The study of the matter, its composition,
properties, and the changes it undergoes.
• Applied Chemistry is the using chemistry to
attain certain goals, in fields like medicine,
agriculture, and manufacturing
• Pure chemistry gathers knowledge for
knowledge sake
Types of Chemistry
• Analytical Chemistry studies composition of
substances.
• Inorganic Chemistry substances without
carbon
• Organic Chemistry compounds containing
carbon
• Biochemistry- Chemistry of living things
• Physical Chemistry studies behavior of
substances
Chemistry is
• A natural science with a language and its
own vocabulary.
• A way of thinking.
What is Matter?
• Matter is anything that takes up space and
has mass.
• Mass is the amount of matter in an object.
– Mass is resistance to change in motion
along a smooth and level surface.
– Volume – measure of 3D space
Types of Matter
• Pure Substance- a particular kind of matter
- pure
• Mixture- more than one kind of matter
Substances
•
•
•
•
Elements- simplest kind of matter
Cannot be broken down
All one kind of atom.
Compounds are substances that can be
broken down by chemical methods
• When they are broken down, the pieces
have completely different properties
than the compound.
• Made of molecules- two or more atoms
Atoms
•
The smallest unit of an element that
maintains the properties of that element.
Elements
•
•
•
•
•
A pure substance made of only one kind
of atom
Currently 118 elements
90 natural 28 synthetic
Found on periodic table
Identified by 1,2, or 3 letter chemical
symbol
Chemical symbols
• There are 118 elements
• First letter always capitalized second and
third never
• Don’t need to memorize
• Some are from Latin or other languages
H= Hydrogen
Au= Gold
Uub=Ununbibium
Elements cont.
•
•
Majority are metals (found on the left side
of periodic table)
Nonmetals on the right of stair step line
Compounds
•
•
•
A substance that is made from the atoms
of two or more elements that are
chemically bonded
Chemical Formula – Indicates type and
number atoms in a compound
Ex. H2O = 2 Hydrogen atoms and 1
Oxygen atom
Compounds cont.
•
Molecular Compounds made from
nonmetallic atoms
• Ionic Compounds contain ions
– (usually a metal and nonmetal)
Molecular or Ionic?
C6H12O6
MgCl2
CO2
Molecular
Ionic
Molecular
Metals
•
•
•
•
•
Luster
Good conductor of heat and electricity
Malleability
Ductility
High tensile strength
Nonmetals
•
•
•
Many nonmetals are gases at room
temperature
Solid nonmetals tend to be brittle
Poor conductors of heat and electricity
Mixtures
• A blend of two or more kinds of matter,
each of which retains its own identity and
properties
• The components of mixtures can usually be
separated through physical means
– filtration, distillation, chromatography
Filtration
• Uses a filter to separate substances
– Solid from a liquid
Distillation
• Separates based on boiling points
– liquids
Chromatography
• Separates based on polarity
– What?!?!?!?!?!
• We’ll get to that later
-Liquids or gases
Heterogeneous Mixtures
• Called suspensions and colloids
• Not uniform throughout
– Ex. Chocolate chip cookie, gravel, soil
Homogeneous Mixture
•
•
Called solutions
Mixtures that are uniform throughout
– Kool-aid, air, gold ring
Solutions
• Like all mixtures, they keep the properties
of the components.
• Can be separated by physical means
• Not easily separated- can be separated.
Solutions
• Homogeneous mixture
– Mixed molecule by molecule
– Can occur between any state of matter.
• Solid in liquid- Kool-aid
• Liquid in liquid- antifreeze
• Gas in gas- air
• Solid in solid - brass
• Liquid in gas- water vapor
Flowchart of Matter
Which is it?
Mixture
Compound
Element
Physical Properties
•
A property that can be observed and
measured without changing the
substance.
– Ex. melting point, boiling point, density,
hardness, color, odor
• Freezing Point vs. Melting Point?
States of matter
• Solid- matter that can not flow and has
definite volume.
• Liquid- definite volume but takes the shape
of its container (flows).
• Gas- a substance without definite volume or
shape and can flow.
Physical Change
•
A change that changes appearances,
without changing the composition.
1. Freezing – liquid to solid
2. Melting – solid to liquid
3. Boiling – liquid to vapor
4. Condensation – vapor to liquid
5. Sublimation – solid to vapor
6. Deposition – vapor to solid
Chemical Properties
•
Relates to a substances ability to undergo
changes that transform it into different
substances
– Ex. combust, oxidize, neutralize
Chemical Change
•
A change in which one or more
substances are converted into different
substances
Ex. combustion, oxidation, neutralization
Chemical Reactions
•
Carbon + Oxygen  Carbon Dioxide
– Read as “Carbon and (plus) oxygen
yields carbon dioxide
– Carbon and Oxygen are reactants
– Carbon Dioxide is the product
Chemical Reactions
• When one or more substances are changed
into new substances.
– Reactants- stuff you start with
– Products- What you make
• NEW PROPERTIES
• Not easily reversed
Indications of a chemical
reaction
•
•
•
•
•
Energy absorbed or released
Color change
Gas is released
Light given off
Precipitate- solid that separates from
solution p.255 in text
Example
Homework
• Page 21 #’s 25,31,34,53,54,56,68