Chemistry:  Unit I. Introduction to Chemistry.

Reading assignment 1: Read  & KTU Ch.1.1 & 1.3.  Also, Write three "right there" questions with answers and three "think & search"

questions with answers.

I. Science – The knowledge covering general truth or the operation of general laws especially as obtained and

  tested through the scientific method.  

 A. Scientific Method- A guideline used to pursue answers to many questions or scientific truth.

  1. Observation - A description of the physical world

   a. Qualitative- a description of the a quality or physical nature

   b. Quantitative- a description of quantity or numerical assessment  

  2. Interpretation - An explanation based on observations.  Based on personal bias (how we think & what we

      know).

  3. Hypothesis- "Educated Guess"-  A tentative explanation based on observations and interpretations that

      attempts to predict future events.  Commonly in “If/then” format.  

  4.   Experiment- A format for testing a hypothesis  

    a. experimental variable- "What" is being tested  

    b. experimental group- "Who" is being tested  

    c. control- variables or groups that are not being directly tested but used as comparison. In a control group,

        subjects are exposed to all the same conditions as the experimental group except they are not exposed to

        the experimental variable.

     d. data- measurements or observations that are used to arrive at a conclusion based on the hypothesis

     e. study- an examination of a system in which variables cannot be controlled or manipulated.

      A study can be easily misinterpreted, so care must be taken when analyzing the results.

   5. Conclusion- A statement made to either accept or reject the hypothesis  

    a. Theory- a statement that explains the certain results of a hypothesis

    b. Law- a theory/hypothesis that concisely explains a set of observations and/or experimental data which

        cannot be refuted.  

review: To recap the Scientific Method, here is a slide show. 

Handout: Here is a printable version of the Scientific Method

practice: Quiz over the Scientific Method. 

II. Chemistry

 A. What is Chemistry? 

   -The study of the composition, structure and properties of matter and the reactions by which matter may be

    formed or converted into other forms.  

Assignment 1: Ch. 1 Standardized Test Prep, page 31, 1-13

Reading assignment 2: Read & KTU Ch. 2 pg. 33-53. On page 54 (Study Guide), Identify the top 12 terms and organize them into a Concept Map.

 B. Classification of Matter

  Matter - an object that has mass and takes up space (volume)

handout. Classification of Matter  

  1. Mixture- Two or more kinds of matter that can be separated by physical means.  

        Techniques for physical separations- filtration, straining/sifting, magnetism, & distillation

    a. heterogeneous mixture - non-uniform distribution of matter

    b. homogeneous mixture – uniform distribution  

        solution- another name for a homogeneous mixture  

  2. Pure Substance- matter that cannot be separated by physical processes  

    a. Element- cannot be broken down into simpler forms of matter  

      - chemical symbols- shorthand representation of the elements  

      Groupings of symbols (a way to help you learn symbols)

      i. symbols that don’t match elemental names: (Na, K, Fe, Cu, Ag, Sn, Sb, W, Au, Hg, Pb)

      ii. symbols with single letters that match the elemental names: (H, B, C, N, O, F, P, S, V, Y, I, U )

      iii. symbols with 2 letter the match the elemental names:  (Li, Be, Cl, Br, Ba, Pt, etc.) 

Practice: Learning your symbols.

      b. Compound- pure substances that can be broken down into simpler forms only by chemical processes.  

      - chemical formula- a group of chemical symbols representing a compound  

        Sodium chloride (salt)- NaCl  (1 sodium atom and 1 chlorine atom)

        Carbon dioxide - CO₂  (1 carbon atom and 2 oxygen atoms)  

Image: Matter Classifications. 

Resource: Matter

practice. Classifying matter. Write out your answers to each. answers

Reading Assignment 3:  Read & KTU Ch. 3 pg. 61-91. On page 93, use two concept points from the Study Guide and write a short 

explanation of why they are important in Chemistry Labs.  This models the "author and me" questioning skill. 

 C.   Properties of Matter  

  1. Physical Properties- characteristics of matter that can be measured or observed without changing the 

      composition of the matter.  

     a.  intensive properties- mass independent properties

      -color, shape, composition, shape, taste, smell, etc.  

      i.Temperature- the average heat energy (kinetic) in a substance  

        a. Temperature Scales-

        -Fahrenheit Scale- (32^o - 212^o) degrees

        -Celsius Scale- (0^o-100^o) degrees

           ** Fahrenheit and Celsius are standardized by the melting and boiling points of pure water at a certain atmospheric pressure.

        -Kelvin Scale-

           ** absolute zero- point where no heat energy exists within in an object**  

Image: Temperature Scales 1-- Temperature Scales comparison

practice. Temperature conversions

      ii. Density- mass per unit volume- "apparent heaviness"

       **density of water = 1.0 ^g/cm³ @ 4 ^oC.

Practice.  Calculating Densities

      iii. Specific gravity- ratio of density of matter to density of water

       ** specific gravity has no units. 

Chart listing the specific gravity of common materials

    b. extensive properties- mass dependent properties

      i. heat (Q)- the total amount of heat energy (kinetic energy)  

        -calorie- amount of heat that increases 1 gram of water by 1 ^oC.

        -joule-  1 calories = 4.184  joule

practice: extensive and intensive properties. 

      c.  States of Matter-

  2. Chemical Properties- characteristics that describe the ability of matter to undergo changes in composition 

      where new substances are formed with new properties.

     ex. flammable/combustible, reacts with acids/bases, decomposes under light/uv (light labile), etc.  

 D.   Changes in Properties

   1. Physical Changes- A change in physical properties of matter without a change in the chemical composition  

    a. Melting/Freezing - Solid / Liquid conversion

     b. Evaporation/Condensation - Liquid / Gas conversion

     c. Sublimation  - Solid / Gas conversion  

   2.  Chemical Changes- A change in matter that produces new substances with new properties (chemical reaction)  

    a. reactants- substances that undergo changes

    b. products- new substances that are formed

      precipitate- a solid produced from solution during a reaction  

    c. Ten signs of chemical change  

      1. Bubbles of gas appear

      2. A precipitate forms

      3. A change in color

      4.Temperature changes

      5.Light is emitted

      6.A change in volume

      7.A change in electrical conductivity

      8.A change in melting or boiling point

      9.A change in smell or taste (not to be performed in lab)

      10.A change in chemical or physical properties

Assignment 2: Ch. 2 Standardized Test Prep, pg 59, 1-14

  E.  Scientific Measurements

  1.Accuracy vs. Precision

    Accuracy- the closeness of a measurement to the actual value

    Precision- the reproducibility of a measurement  

   2. Significance of Measurement  

     -all measurements contain exact digits and 1 estimated digit  

    a. Significant Figure Rules

      1. Non-zero digits are always significant.

      2. All zeros between other significant digits are significant.

      3. The number of significant figures is determined starting with the leftmost non-zero digit. The left-most non-zero digit is

          sometimes called the most significant digit or the most significant figure. For example, in the number 0.004205

          the '4' is the most significant figure. The right-hand '0's are not significant. The zero between the '2' and the '5' is significant.

      4. The right-most digit of a decimal number is the least significant digit or least significant figure. Another way to look

          at the least significant figure is to consider it to be the rightmost digit when the number is written in scientific notation.

          Least significant figures are still significant! In the number 0.004205 (which may be written as 4.205 x 10^-3), the '5' is the

          least significant figure. In the number 43.120 (which may be written as 4.3210 x 10¹), the '0' is the least significant figure.

      5. If no decimal point is present, the right-most non-zero digit is the least significant figure. In the number 5800, the least

          significant figure is '8'.

Image: Which figures are significant

Image: Significant Figures in measures

Examples: Measurements

    b. Atlantic/Pacific Rule for Determining Significance

     ** If decimal is Present (Pacific), come in from the left and stop at the first nonzero digit, remaining places are significant.

     ** If decimal is Absent (Atlantic), come in from the right and stop at the first nonzero digit, remaining places are significant  

      Note:  If there are zeros in a number that are significant but can't be represented separately from non-significant zeros,

      then we use scientific notation

      example:   Represent the measure 2,300 ft that is significant to the tens but not the units. 

      = 2.30 x 10³ ft  (Answer has only 3 significant figures.  Instrument was accurate to the hundreds of feet)

Practice.  Identifying Significant Figures

Practice: Taking measures with significant figures

   3. Significant figures in calculations

      a. addition/subtraction- The answer will contain the last significant place as the number with the least accurate significant place.  

        example:

      b. multiplication/division- an answer will contain the same number of sig figs as that least number of sig figs in any number  

        example

    4.     Metric System-  (SI system- International System of Units-c.1960) 

      Standards for measurements used by scientists. Where do they come from? click here 

Video: What is a mole? TedEd

      a. All metric measurements are related by factors of 10  

        -this avoids confusion when converting from one unit measure to another.

       examples:

       1 Megameter  = 1 x 10⁶   meters or 1,000,000 meters

       1 milliliter     =     1 x 10^-3 liters  or  0.001  liters  (also thought of as  1 liter =   1000 mL) 

       ** To define the conversion between two units, calculate the powers of ten difference, thus the conversion.

        ex. The difference between nano- and milli- is 6 powers of ten., 

       therefore the conversion is 1 milligram = 1,000,000 nanograms 

    5. Problem Solving with measurements.

      a. Equality- a statement of two things being equal

         ex.  1 foot = 12 inches

      b. Conversion- an equality written as a fraction.

        - a conversion has the value of 1.  What happens when you multiply something by 1?

           1 foot  

         12 inches

       c. Unit Analysis (Dimensional Analysis)

        - a format for solving problems.  The advantage is that it organizes your math problems and allows you to cancel out units as 

        you progress through the problem.

Practice & Tutorial: Fun with dimensional analysis

Practice & Tutorial: Conversions practice. There are problems at the bottom and answers for each.

Assignment 3:  Ch. 3 Standardized Test Prep, pg 99, 1-12

unit Review Practice: Here is some practice quizzes for you to test your understanding over UNIT I.