Chapter 1

Section 1.1 Chemistry is a physical science.

Objectives:

1.      Define chemistry.

2.      List examples of the branches of chemistry.

3.      Compare and contrast basic research, applied research and technological development.

        What is chemistry?   Chemistry is the study of the properties, composition, and structure of matter and the energy that is released or absorbed during the changes that matter undergoes.  In the dictionary chemistry is defined as “1.  The science that treats of the composition of substances and of the transformations which they undergo; 2.  chemical composition, properties, or process.”  The field of chemistry can be divided into the following major branches:

        inorganic - study of all elements and their compounds except carbon compounds

        organic - study of carbon compounds (living or once living materials)

        analytical - study of the identification of the components and the determination of the composition of substances

        physical - study of the properties and changes of matter and their relation to energy

        biochemistry - study of composition and changes in composition of living organisms

        theoretical chemistry – use of math and computers to understand the principles behind observed chemical behavior and to design and predict the properties of new compounds

        Chemistry involves scientists who work with chemicals.  A chemical is defined as any substance with definite composition.  

Chemistry overlaps with many fields.  Agriculture, medicine, nuclear, manufacturing and various other industries all include a knowledge of chemical principles.  It contributes to biology, geology, and physics to name a few of the sciences.  

        

        What might a chemist do?

1.  Research and develop new products

2.  Engineer the production of chemical

3.  Reduce/clean up pollution

4.  Dye clothing

5.  Forensics

6.  Medicine

7.  Analyze the chemical composition of substances

8.  Analyze the chemical properties of substances

        Each of the above jobs requires a knowledge of chemicals and their properties.  That knowledge leads to basic research which is carried out for the sake of increasing knowledge, such as how and why a reaction occurs.  It is also called pure science.  Applied research is generally carried out to solve a specific problem.  Technological development involves the production and use of products that improve our quality of life.  Technological applications lag behind basic discoveries.  All three overlap.  Discoveries may trigger ideas for applications.    

        Alchemists believed that all matter consisted of 4 elements, fire, wind, water, and air.  Each of these exhibited 2 of the 4 basic properties, moistness, dryness, hotness, and coldness. It was believed that by altering these properties an element could be transformed into another element.  The most provocative transformation was from some element to gold.  

Section 1.2   MATTER AND ITS PROPERTIES

Objectives:

1.      Distinguish between chemical/physical properties.

2.      Classify changes as chemical or physical.

3.      Explain the gas, liquid, and solid states in terms of particles.

4.      Distinguish between a mixture and a pure substance.

For Pre-AP Chemistry add

• Distinguish among the classes of matter.
• Classify matter as to type.     
  

        There are many pieces of information, or properties, which may be used to identify matter.  Matter is anything that has mass and takes up space (volume).  Mass and volume are ways of describing a quantity of matter.  Weight is another way.  Upon what do these descriptions depend?  

        Weight depends gravity and so is affected by location.  It is measured with spring scale and its unit is the newton.    

        Volume is the amount of space occupied by matter and, for gases it depends upon temperature and pressure.  It may be measured in several ways.  For regular solids, the dimensions may be measured and then the appropriate volume formula may be used.  For irregular solids, the water displacement method may be used.  For liquids, a graduated cylinder may be used but the temperature must be recorded.  For gases, both temperature and pressure must be recorded to measure volume.  The unit of volume is the cubic centimeter or the liter.

BOTH weight and volume may vary.

        Mass, however, is a measure of matter which is not affected by temperature, location, or other factors.  It is measured in grams and is measured by a balance.  

        Matter is composed of fundamental building blocks called atoms.  These are the smallest pieces into which matter can be broken and still maintain its identity.  Atoms can be broken down(into protons, neutrons, and electrons) but they will no longer be the same substance.

        If all the atoms in a sample are of the same kind then the sample is said to be an element, which is a pure substance.(Give examples.)  If the matter is made up of two or more different atoms chemically bonded together, then it is a compound, also a pure substance having its own unique set of properties.(Give examples.)

        Every sample of matter has different characteristics.  These characteristics, or properties, help distinguish between kinds of matter and separate one kind of matter from another.  Some examples are

1.  state

2.  color

3.  textures

4.  heavier

5.  stronger

6.  changes that are characteristic

        We are trying to learn why each kind of matter is special and can change as it does.  This will enable us to produce new materials with desirable properties and to control other processes which occur naturally.  It may also enable us to control pollutants.  

States of matter

        There are five states of matter:  solids, liquids, gases, plasmas, and Bose-Einstein condensates*.  Each has a definite set of characteristics associated with it.  All matter may exist in these forms but the state at room temperature is taken as the normal state.  (List 6 properties of each common state.)

NOTE:  A vapor is a substance that, although in the gaseous state, is generally a liquid or solid at room temperature.  

*  Bose-Einstein condensates are a brand new “fuzzy” megaparticle:  All identical atoms coalesced into a single entity, about 2/1000 of and inch in diameter.  It was first reported in 1995 by a group at the University of Colorado.  It was formed in the coldest place anywhere in the universe --- 20 nanokelvins or 36 billionths of a degree Fahrenheit above absolute zero.  At such low temperatures speed goes to zero and location becomes indefinite, wavelike.  These states were predicted by Einstein about 70 years ago.  The low temperatures required are produced by bouncing laser light off matter.  Each atom is really a magnet and so an external magnet can be used to keep atoms together.  BEC may eventually be used in atomic clocks or in supersensitive measuring devices.

Classification of matter        

        The appearance of matter is endless.  There are 2 kinds:  homogeneous and heterogeneous.  The former is matter that has uniform characteristics throughout.  The latter is matter that has parts with different characteristics.

        There are two main classes.  A substance is a variety of mater, all samples of which have the same properties or characteristics.  It may take any of the four* states of matter.  it must be uniform in composition and definite in composition.  It must be pure.    

 *BEC is best with active metals at this point.  

        There are two subclasses of substances.  One is elements and the other is compounds.  Elements are composed of only one kind of atom and cannot be further subdivided and retain their identity.  They are the simplest forms of matter and are considered to be the building blocks of all other substances.    Compounds are composed of two or more kinds of atoms which are chemically bound together in a definite ratio.  They can be broken into their elements by a chemical change.  They may be organic or inorganic by must have unique properties, unlike those of constituent  elements.  

        Elements

1.  118 elements

2.  92 naturally occurring

3.  metals, nonmetals and semimetals

4.  free state or combined state as in ores

5.  on Earth

        a.      oxygen 46.7%

        b.      silicon  27.7%

        c.      aluminum 8.1%

        d.      iron  5.0%

        e.      sodium  2.7%

        f.      potassium  2.5%

        g.      magnesium  2.1%

        h.      all others  1.6%

6.  hydrogen - most abundant in universe

7.  air

        a.  nitrogen  78%

        b.  oxygen  21%

        c.  argon  0.93%

        d.  carbon dioxide  0.03%

        e.  other noble gases - trace amounts

8.  C, H, N are important in living things but are scarce in Earth’s crust.  They along with O compose 99.4% of all atoms in the human body.

        The other class is mixtures.  A mixture is a physical blend of 2 or more substances.  It has a variable composition.  Most natural materials are mixtures.  They may be separated by ordinary physical means.  [evaporation, condensation, distillation, vaporization, sublimation]  All components in a mixture retain their individual properties.  

        

        Mixtures are divided into two subclasses, homogeneous and heterogeneous.  Homogeneous mixtures, solutions, are uniform in composition and are considered to be one phase*. Heterogeneous mixtures are nonuniform and are in two or more phases.   

*  Any part of a system with uniform composition and properties is a phase.

*Distillation is a process of purifying by first vaporizing and then condensing a substance into another flask.  This process leaves the impurities behind in the reaction flask.

*Electrolysis is another way of separation but involves the breaking of chemical bonds and so is not a physical means of separation.

        There are six types of solutions:  liquid-liquid, liquid-gas, liquid-solid, solid-solid, solid-gas, gas-gas.  The term alloy refers to a solid-solid mixture.  The term amalgam refers to an alloy containing mercury.

        Properties are the characteristics or features of matter with which it is identified.  There are physical properties that indicate what can be observed by examination, without changing composition.  Thus, only physical changes occur. There are two kinds of physical properties, extensive and intensive.  Extensive properties refer to how much of a sample is present and cannot be use for identifying the substance.  Intensive properties refer to identifying properties such as color, texture, and so on.  

        There are others, called chemical properties, which indicate behavior (or a lack thereof), upon contact with other substances or sources of energy and a chemical change occurs.   A new substance is formed as a result of a chemical investigation.  This is a chemical reaction.  Here a product is formed from reactants.  If the product is a solid that separates from solution, it is called a precipitate.  In any reaction mass may not be created or destroyed, only rearranged.  This is the law of conservation of matter.  All atoms remain in tact but may be bonded differently or ionized.  Likewise, atoms may not suddenly appear from nowhere.  The alchemists could not make gold atoms appear where lead atoms had been.    

There are several indicators that tell when a chemical change has occurred.  

        1.      The process is difficult to reverse.

        2.   A color change may be an indicator.

        3.   An odor change may be an indicator.

        4.   A solid may be produced.

        5.   A gas may be produced.

        6.   Heat energy is usually absorbed or evolved.  (although this may also indicate a physical change)

        7.   Light or sound may be evolved.   

Energy is the capacity for doing work.   Work is the moving of something over a distance.  The unit of energy is the joule.  All chemical and physical processes involve the absorption or emission of energy as they progress.  If energy is emitted during a reaction, the process is said to be exothermic.  If energy is absorbed during a reaction, the process is said to be endothermic.

*Heat is energy in transit.  It is energy transferred as a result of temperature differential.  

        Properties may also be classified as to those that are affected by the amount of material present and those which are not.  Extensive properties depend upon how much sample is present whereas intensive properties do not depend on the size of sample.  Intensive properties may be used to identify substances but extensive ones may not.  Some intensive properties are ductility, malleability, conductivity, luster, and density.

Section 1-3 ELEMENTS

Objectives:

1.  Write symbols if given names.

2.  Write names if given symbols.

3.  Describe the arrangement of the periodic table.

4.  List characteristics which distinguish metals, nonmetals, and metalloids.   

(See www.webelements.com)

sodium   natrium                Unq unnilquadium        rutherfordium

potassium  kalium               Unp unnilpentium        dubium

antimony         stibium                        Unh unnilhexium seaborgium

copper   cuprum                 Uns unnilseptium        bohrium

gold       aurum                        Uno unniloctium hassium

silver     argentum                     Une unnilennium     meitnerium

iron             ferrum                 Unu unnilunium              

lead       plumbum                      Uuu unununium

mercury    hydrargyrum                  Uub ununbium

tin             stannum                 Uuq ununhexium

tungsten        wolfram                 Uuo ununoctium

*Always print.

*Always capitalize the first letter.

*Use a second letter for uniqueness(lower case).

        The periodic table is the systematic organization of all of the known elements.  The vertical columns are called groups, or families.  They are so named because they have similar properties due to the valence configurations of the atoms.  Groups 1,2, 13, 14, 15, 16, 17, and 18 are called the representative elements.  Groups 3-12 are called the transition elements.  The horizontal rows are called periods.  Physical and chemical properties change somewhat regularly as one moves across a row.  The changes in properties at regular intervals is known as periodicity.  Below the periodic table are the lanthanide series and the actinide series elements.  They are metals that really fit after element 57 and element 89 respectively.   They are placed on the page in this position to keep the table from becoming too wide.    

        There are 3 types of elements.  Metals are elements that conduct heat and electricity well, are ductile, are malleable, have luster, are solids(except mercury), and have 1-3 valence electrons.  Nonmetals are elements that do not conduct well and so are used as insulators.  They are brittle and dull.  They may be solids, liquids(bromine), or gases at room temperature.  They have 5-8 valence electrons.  Metalloids, or semimetals, have some properties of both metals and nonmetals.  They are solids at room temperature.  They tend to be semiconductors and are not as brittle as nonmetals or as malleable as metals.  The noble gases are the elements of group 18.  They are very nonreactive due to the stable valence shell containing 8 electrons.  

Back