1-1 Is the study of matter, its properties, the changes that matter undergoes, and the energy associated with these changes.

1-2 Definitions Chemical Properties those which the substance shows as it interacts with, or transforms into, other substances such as flammability, corrosiveness Matter anything that has mass and volume -the “stuff” of the universe: books, planets, trees, teachers, students Properties the characteristics that give each substance a unique identity Physical Properties those which the substance shows by itself without interacting with another substance such as color, melting point, boiling point, density

1-3 Figure 1.1 Physical change A substance alters its physical form, not its composition Chemical change A substance is converted into a different substance The distinction between physical and chemical change.

1-4 Some Characteristic Properties of Copper Table 1.1 Physical PropertiesChemical Properties reddish brown, metallic luster easily shaped into sheets (malleable) and wires (ductile) good conductor of heat and electricity density = 8.95 g/cm 3 melting point = C boiling point = C slowly forms a basic blue-green sulfate in moist air reacts with nitric acid and sulfuric acid slowly form a deep-blue solution in aqueous ammonia

1-5 Figure 1.2 The physical states of matter.

1-6 Sample Problem 1.1 Distinguishing Between Physical and Chemical Change PROBLEM: Decide whether each of the following process is primarily a physical or a chemical change, and explain briefly: SOLUTION: (a) Frost forms as the temperature drops on a humid winter night. (b) A cornstalk grows from a seed that is watered and fertilized. (c) Dynamite explodes to form a mixture of gases. (d) Perspiration evaporates when you relax after jogging. (e) A silver fork tarnishes slowly in air. (a) physical change(b) chemical change(c) chemical change (d) physical change(e) chemical change

1-7 energy due to the position of the object or energy from a chemical reaction Potential Energy Kinetic Energy energy due to the motion of the object Energy Energy is the capacity to do work. Potential and kinetic energy can be interconverted.

1-8 Energy Energy is the capacity to do work. Figure 1.3B less stable more stable change in potential energy EQUALS kinetic energy A system of two balls attached by a spring. The potential energy gained by a stretched spring is converted to kinetic energy when the moving balls are released.

1-9 Energy Energy is the capacity to do work. Figure 1.3C less stable more stable change in potential energy EQUALS kinetic energy A system of oppositely charged particles. The potential energy gained when the charges are separated is converted to kinetic energy as the attraction pulls these charges together.

1-10 Scientific Approach: Developing a Model Observations : Natural phenomena and measured events; universally consistent ones can be stated as a natural law. Hypothesis: Tentative proposal that explains observations. Experiment: Procedure to test hypothesis; measures one variable at a time. Theory ( Model ): Set of conceptual assumptions that explains data from accumulated experiments; predicts related phenomena. Further Experiment: Tests predictions based on model. revised if experiments do not support it altered if predictions do not support it

1-11 Alchemist at Work

1-12 Lavoisier (1743 – 1794) Debunked phlogiston theory Demonstrated the true nature of combustion Named oxygen

1-13 A Systematic Approach to Solving Chemistry Problems Problem statement Plan Clarify the known and unknown. Suggest steps from known to unknown. Prepare a visual summary of steps. Solution Check Comment and Follow-up Problem

1-14 Sample Problem 1.2 Converting Units of Length PROBLEM: To wire your stereo equipment, you need 325 centimeters (cm) of speaker wire that sells for $0.15/ft. What is the price of the wire? PLAN: Known - length (in cm) of wire and cost per length ($/ft) We have to convert cm to inches and inches to ft followed by finding the cost for the length in ft. length (cm) of wire length (ft) of wire length (in) of wire Price ($) of wire 2.54 cm = 1 in 12 in = 1 ft 1 ft = $0.15 Follow up Problem 1.2 A furniture factory needs 31.5 ft 2 of fabric to upholster one chair. The supplier sends the fbric in bolts of exactly 200 m 2. What is the maximum number of chairs that can be upholstered by 3 bolts of fabric? 1 m = ft

1-15 Table 1. 2 SI Base Units Physical Quantity (Dimension) Unit Name Unit Abbreviation mass meter kg length kilogram m timeseconds temperaturekelvinK electric currentampereA amount of substancemolemol luminous intensitycandelacd

1-16 Common Decimal Prefixes Used with SI Units Table 1.3

1-17 Substance Physical State Density (g/cm 3 ) Densities of Some Common Substances * Table 1.5 HydrogenGas OxygenGas Grain alcoholLiquid WaterLiquid Table saltSolid 2.16 AluminumSolid 2.70 LeadSolid11.3 GoldSolid19.3 * At room temperature(20 0 C) and normal atmospheric pressure(1atm).

1-18 Sample Problem 1.5 Calculating Density from Mass and Length PROBLEM: Lithium (Li) is a soft, gray solid that has the lowest density of any metal. If a slab of Li weighs 1.49 x 10 3 mg and has sides that measure 20.9 mm by 11.1 mm by 11.9 mm, what is the density of Li in g/cm 3 ?

1-19 Figure 1.12 The freezing and boiling points of water.

1-20 Temperature Scales and Interconversions Kelvin ( K ) - The “Absolute temperature scale” begins at absolute zero and only has positive values. Celsius ( o C ) - The temperature scale used by science, formally called centigrade, most commonly used scale around the world; water freezes at 0 o C, and boils at 100 o C. Fahrenheit ( o F ) - Commonly used scale in the U.S. for our weather reports; water freezes at 32 o F and boils at 212 o F. Kelvin = o C o C = Kelvin o F = (9/5) o C + 32 o C = [ o F - 32 ] 5/9

1-21 Sample Problem 1.6 Converting Units of Temperature A child has a body temperature of 38.7 o C. (a) If normal body temperature is 98.6 o F, does the child have a fever? (b) What is the child’s temperature in Kelvin?

1-22 The number of significant figures in a measurement depends upon the measuring device. Figure o C32.33 o C

1-23 Rules for Determining Which Digits are Significant Leading zeros are not significant. If the measured quantity has a decimal point start at the left of the number and move right until you reach the first nonzero digit. Count that digit and every digit to it’s right as significant. Numbers such as 5300 L are assumed to only have 2 significant figures. A terminal decimal point (or a bar) is often used to clarify the situation, but scientific notation is the best! Zeros that end a number and lie either after or before the decimal point are significant; thus ml has four significant figures, and L has four significant figures also. If the measured quantity does not have a decimal point start at the right of the number and move leftt until you reach the first nonzero digit. Count that digit and every digit to it’s left as significant.

1-24 Sample Problem 1.7 Determining the Number of Significant Figures For each of the following quantities, determine the number of significant figures in each quantity. SOLUTION: (b) g(a) L(c) 53,069 mL (e) 57,600. s(d) m (f) cm 3 (b) 4sf (a) 2sf (c) 5sf (e) 5sf (d) 4sf (f) 4sf

1-25 Rules for Rounding Off Numbers 1. If the digit removed is more than 5, the preceding number increases by rounds to 5.38 if three significant figures are retained and to 5.4 if two significant figures are retained. 2. If the digit removed is less than 5, the preceding number is unchanged rounds to if three significant figures are retained and to 0.24 if two significant figures are retained. 3.If the digit removed is 5, the preceding number increases by 1 if it is odd and remains unchanged if it is even rounds to 17.8, but rounds to If the 5 is followed only by zeros, rule 3 is followed; if the 5 is followed by nonzeros, rule 1 is followed: rounds to 17.6, but rounds to Be sure to carry two or more additional significant figures through a multistep calculation and round off only the final answer.

1-26 Precision and Accuracy Errors in Scientific Measurements Random Error - In the absence of systematic error, some values that are higher and some that are lower than the actual value. Precision - Refers to reproducibility or how close the measurements are to each other. Accuracy - Refers to how close a measurement is to the real value. Systematic error - Values that are either all higher or all lower than the actual value.

1-27 Figure 1.16 precise and accurate precise but not accurate Precision and accuracy in the laboratory.

1-28 systematic error random error Precision and accuracy in the laboratory. Figure 1.16 continued