Chemistry: The Science of Matter
I. Science
A. The systematic use of observation to study the physical universe.
1. Systematic—methodical, purposefully regular, step by step
2. Observation—use of the 5 senses
a) Sight—eyes
b) Hearing—ears
c) Smell—nose
d) Taste—tongue
e) Touch—skin
3. Physical—dealing with that that is material
a) Not spiritual
b) Can be observed with the 5 senses
II. The Puzzle of Matter
A. A Picture of Matter
1. The 3 basic sciences
a. Chemistry—the science that deals the structure and properties of matter
b. Physics—the science that deals with the energy of matter
c. Biology—the science that deals with living matter
2. Composition, Structure, and Behavior
a. Matter—anything that has mass and takes up space
1) Mass—the measure of the amount of material in an object
2) Space—volume
b. Structure of matter—refers to
1) composition
2) how that matter is organized
c. Properties of matter describe
1) characteristics of matter
2) behavior of matter
3) the changes that matter undergoes
4) Two types
(a) Physical—properties that can be observed and measured without a change in the substance
(b) Chemical—properties that cannot be observed or measured without a change in the substance
3. Examining Matter: The Macroscopic View of Matter
a. Macroscopic view—matter that is large enough to be seen, level where chemistry starts
b. Gives us clues as to what is going on; however, not the details
4. The Submicroscopic View of Matter
a. gives a glimpse into the world of atoms
b. smaller than what can be seen with the most powerful microscopes
c. a period would contain 100 quintillion (1,000,000,000,000,000,000,000 atoms (1 x 1021) ) atoms of Carbon.
B. Using Models in Chemistry
1. Models connect the Macroscopic and Submicroscopic views
a. Scientific model—a thinking device that helps one understand and explain macroscopic and submicroscopic observations.
b. Model—Hill version—a simplified picture
C. Classifying Matter
1. The need—understanding and organization
2. Classification by Composition
a. Qualitative data—data described in words, no measurements
b. Quantitative data—data using numbers obtained from a measurement
3. Pure substance or a mixture?
a. Pure—all of the matter is the same substance
b. Substance—matter with the same fixed composition and properties
c. Mixture—a combination of two or more pure substances
1) Homogeneous—the same throughout
2) Heterogeneous—different throughout
d. Solution—a homogeneous mixture
1) Solvent—the substance doing the dissolving
2) Solute—the substance getting dissolved
3) Aqueous—water is the solvent in the solution
4) Alloys—solid solutions, normally of different metals
D. Substances: Pure Matter
1. Element—a substance that cannot be broken down into a simpler substance by ordinary chemical means
a. Symbol—shorthand way to write an element
1) First letter is always capitalized
2) Second letter is never capitalized
b. Names—derived usually from Latin
c. 92 naturally occurring elements
1) actually less, because of unstable compounds of Tc, Pm, At, Fr
2) actually more, because of Np and Pu
2. Compound—a substance made of two or more elements chemically bonded together
a. Formula—shorthand way to write a compound
1) Three types
a) Molecular—chemical formula—show the element and the number of atoms
b) Emperical—molecular formula in lowest terms
c) Structural—shows the structure of the molecular formula
2) Names—will discuss later
III. Properties and Changes of Matter
A. Identifying Matter by Its Properties
1. States of Matter—temperature dependent, kinetic and attractive forces
a. Types
1)Solid—A>K
2) Liquid—A=K
3) Gas—A<K
4) Plasma—particles moving so fast that it knocks of particles from atoms
b. Phase changes
1) Melting—changing from a solid to a liquid
2) Evaporation—changing from a liquid to a gas
3) Condensation—changing from a gas to a liquid
4) Freezing—changing from a liquid to a solid
5) Sublimation—changing from a solid to a gas, or a gas to a solid
6) Volatile—substance will change to a gas at room temperature
2. Density
a. the amount of matter contained in a unit of volume
b. D=M/V
c. Normal units
1) g/ml—solids and liquids
2) g/l—gasses
B. Chemical Properties and Changes
1. Law of conservation of mass—in a chemical change, matter is neither created nor destroyed, but can change form
2. Energy—ability to do work
a. Exothermic reactions—energy is given off during a reaction (burning)
b. Endothermic reactions—energy is absorbed (ice packs, photosynthesis)