Post on 29-Jan-2016
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Chapter 1Chemistry: 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
Molecular
MgCl2Ionic
CO2
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?
ElementCompoundMixture
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