Notes

Outline

Introduction:Matter and Measurement

Chemistry And Society Chemistry- Science dealing with the chemical and physical interaction of matter Facets of Society Impacted By Chemistry Agriculture Medicine Textile Industry Petroleum Industry

Microscopic vs Macroscopic View of Matter Microscopic- View at the molecular level Macroscopic-Visual view (ie: what we see)

Physical States of Matter Gas- Matter that takes on the shape and volume of its container.  Particles having the maximum freedom of movement(entropy).Possesses highest energy Liquid- Matter that takes on the shape of the container but not necessarily its volume.Particles have moderste degrees of freedom and energy Solid- Matter that takes on its own shape and volume.  Particles have the least degree of freedom and energy

Types of Matter Pure Substances Elements Compounds Mixtures

Classification of Matter Elements- A pure substance consisting of only one kind of atom and in which no further chemical breakdown is possible Approximately 112-118 (depending on who you talk to) Compounds- A pure substance that consists of two or more elements chemically combined and in which further breakdown into its separate elements is possible

Classification of Matter (continued) Mixture- Two or more pure substances that have been physically combined Heterogeneous Mixtures- Mixtures that are not uniformly distributed Example-Sand and Salt, Oil and vinegar Homogeneous Mixture-Mixtures that are uniformerly distributed Example- any solution such as a salt solution, metal alloy

Elements and Symbols

Molecular Elements Elements that exist as molecular units at room temperature containing the same type of atoms in the molecular unit Examples H2, O2, N2, F2, Cl2, Br2, I2, P4, S8

T-1.15 Flowchart Elements,Compounds and Mixtures

Separation of Mixtures Resolution-Physical separation of substances in a mixture using differences in their Physical Properties Types of Resolution Filtration (solid/liquid heterogeneous mixtures) Decantation (solid/liquid heterogeneous mixtures) Distillation(solid/liquid liquid/liquid or gas/liquid homogeneous mixtures) Fractional Crystallization(solid/liquid homogeneous mixture) Chromatography

Distillation Techniques of resolution Simple Distillation Substances that have a 100 degree or better separation in boiling points Fractional Distillation Substances that have less than 100 degrees separation in boiling points Vacuum (Reduced Pressure) Distillation For substances that would decompose before reaching their normal boiling point Steam Distillation For substances that would be attracted to water by Hydrogen bonding and would distill over near the boiling point of water

T-1.11 Simple Distillation

Intensive vs Extensive Properties Property- a behavioral characteristic of matter Intensive property- a property that allows for the identification of a substance and do not depend upon the quantity for their measurement Examples-melting point, boiling point, sublimation point Extensive Properties- a property that indicates the quantity of a substance Examples- mass, volume

Physical vs Chemical Properties Physical Property- Properties whose measurements do not result in a chemical change Examples-melting point, boiling point, solubility, sublimation point Chemical Property- Properties whose measurements do result in a chemical change Examples- Oxidation Potential, Heat of Combustion, Cell Potential

Physical and Chemical Change Physical Change-Change that takes place with matter in which no compositional change takes place(atoms do not undergo rearrangement) Examples- Boiling, melting, sublimation, solution formation Chemical Change- Change that takes place with matter in which there is a compositional change (atoms do undergo a rearrangement) Examples-Rusting of metal, boiling an egg, precipitation of solid by mixing two solutions

T-1.8 Scientific Method

Scientific Method 1. Literary Search 2. Formulate Hypothesis(educated guess) 3. Test Hypothesis (design experiment) 4. Collect Data (qualitative and quantitative observations) 5. Determine relationships (trends and patterns) between variables 6. Formulate Conclusions and reformulate hypothesis

Nature of a Theory Theory- a model of an observable phenomenon which allows for the phenomenon to be explained and predicts outcomes when phenomenon is altered Theories are supportable by experimental results but never proven

Metric (SI) Prefixes Giga(G)    109 Mega(M)   106 Kilo(k)       103 Deci(d)      101 Milli(m)      10-2 Micro(  )     10-6 Nano(n)      10-9 Pico (p)       10-12 Femto(f)      10-15

T-6 Seven SI Base Units

Metric Mass Units Kilogram(kg)-base unit 1kg = 2.2 lbs Gram (g or gm) 1000 grams = 1 kg 30 grams = 1 dry ounce Milligram (mg) 1000 mg = 1 g

Metric Dimensional Units Meter(m)-base unit 1 m = 39.36 inches = 1.09 yds Kilometer(Km) 1Km = .62 miles 1 Km = 1000 m Centimeter (cm) 1 cm = 2.54 inches 1 cm = .01 m Millimeter (mm) 1 mm = .001 m     1000 mm = 1 m    10 mm = 1 cm

Temperature Measurement Types of Temperature Scales Fahrenheit Scale Celsius(or Centigrade) Scale Kelvin Scale Relationships Between Scales F = 1.8C + 32 C = (F-32) / 1.8 K = C + 273.15

T-1.22 Comparison of Temperature Scales

Metric Volume Units Cubic meter (m 3)-base unit 1 m 3 = 1 X 10 6 cc Cubic centimeter (cc or cm 3) 1 cc = 1 ml Milliliter (ml) 1 ml = .001 liters 30 ml = 1 liquid ounce Liter(l) 1 l = 1000 ml = 1000 cc 1 l = 1.06 quarts

Deriving Volumetric units from Dimensional Equivalencies Relationship between cubic feet and cubic inches 1 ft = 12 inches (1 ft) 3 = (12 inches)3 1 ft 3 = 1728 in 3

Density Measurement Density- Relationship between the mass of an object and its volume Density (D) = Mass(m) / Volume(V)

Determining a Standard Scientific Notation of a Number(Appendix A) Locate the decimal Move the decimal either to the right or left so as to have one non-zero digit remaining to the left of the moved decimal If the decimal had to be moved to the left, count the number of positions and use that number as the exponent of 10 to be multiplied by the number with the repositioned decimal

Determining Standard Scientific Notation of Number (cont) 4. If the decimal had to be moved to the right, count the number of positions moved and use the negative value of that number as the exponent of 10 to be multiplied by the number with the repositioned decimal Example- 144.7 would be 1.447 X 10 2 0.00492 would be  4.92 X 10 –3

Multiplying Notated Numbers Carry out the multiplication of the numbers to the left of the powers of 10 Multiply the exponential parts by adding the exponents of the powers of 10 and express as a total exponential of 10 Multiply results in step 1 by step 2 Adjust the decimal so the result will be in standard form Example:

Division Using Notated Numbers Divide the numbers to the left of the exponential parts first Divide the exponential parts by subtracting the exponent in the denominator from the exponent in the numerator expressing the difference as the exponent of 10 for the answer Multiply the results of step 1 ny the results in step 2 Adjust the decimal so the results will be in standard form Example:

Adding and Subtracting Exponential Numbers  Adjust the decimal on each notation so they all have the same exponent Add or subtract the numbers to the left of the exponential parts Multiply the sum or difference to the common exponential Adjust the decimal so that the answer will be in standard form Example:

Precision vs Accuracy Precision- the internal consistency (closeness) of a set of events to one another Accuracy- The external consistency (closeness) of a set of events when compared to a standard (authoritative or expert value) Analogy- Dart Board

T-5 Comparing Precision And Accuracy

Reporting Measured Values Always report measured values with the first position of estimation as the last reported significant digit Example: If thermometer reads + or - .5 degrees then a temperature of 25 should read 25.0.  The tenths position is the estimated position

Exact Numbers Exact Numbers are integers, fractions, or exact counts

Determining Significant Digits In A Computed Number 1. All leading zeros (zeros with no non-zero digits to their left) are considered not significant Example: 0.000987 has three significant digits all zeros are not significant 2.Trailing zeros and zeros between other digits are considered significant Example: 1.0040 has five significant digits.  All of the zeros are trailing or between other digits 3. All non-zero digits are significant

Determining the Significant Digits In a Number without an Indicated Decimal Numbers with no indicated decimal should be rewritten in standard scientific notation counting only the digits that appear before the exponential part. Example:  93,000,000 has no indicated decimal so rewrite it in scientific notation 9.3 X 10 7 Then the number has two significant digits. If written as 9.30 X 10 7 then the indicated significant digits is three

Rules For Rounding Off 1.Locate the last digit to be reported significant 2. If the digit to its right is less than 5 then round that digit and all further digits off. Give example 3. If the digit to the right is 5 or greater than 5 then the digit and all others further out are to be rounded off and the last reported digit increased by one. Give example

Determining Significant Digits For a Product or Quotient Rule-The product or quotient can have no more significant digits than the least digited number involved in the computation Example:23.9 (16.782)= product with three significant digits 0.002613 / 3.4873 = quotient with four significant digits

Determining the Significant Digits of a Sum or Difference Rule-The Sum or Difference can be no more precise than the least precise term in the operation.  In other words, it can have no more digits to the right of the decimal than the number with the least number of positions to the right of the decimal. Example:  24.572 + 4.61 + 8.4 = 37.582 = 37.6

Solving Math Problems 1.Read the problem carefully with understanding 2. Identify the given data directly and indirectly stated in the problem 3. Identify the requested result to be computed 4. Identify the type of problem involved

Solving Math Problems (cont) 5.Select a method of solving the problem using either the label factoring(conversion factor) method or algebraic method 6. Apply the solution 7. Check result for reasonableness

Conversion Factor Method 1. Read the problem 2. Identify the given units involved 3. Identify the requested unit involved 4. Identify the relationship (equivalency) between the given unit and the requested unit (A units = B units) 5. Using the relationship identify the two possible conversion factors (ratios) A unit / B units or B unit/ A unit

Conversion Factor Method (cont) 5. Multiply the given value with its unit by one of the two conversion factors so that the given unit is cancelled 6. Complete the computation for the final answer including the requested unit.

Multiple Conversions Convert a value in feet to nanometers Feet --àmeters--ànanometers Convert a value in pounds to milligrams Pounds --à grams--àmilligrams