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Chem 106, Prof. J.T. Spencer 1 u What is Chemistry –Study of the “Physical” Properties Matter (Form and Function) –Study of How Matter Changes (Reactivity)

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Presentation on theme: "Chem 106, Prof. J.T. Spencer 1 u What is Chemistry –Study of the “Physical” Properties Matter (Form and Function) –Study of How Matter Changes (Reactivity)"— Presentation transcript:

1 Chem 106, Prof. J.T. Spencer 1 u What is Chemistry –Study of the “Physical” Properties Matter (Form and Function) –Study of How Matter Changes (Reactivity) u Benefits of Chemistry –Pharmaceuticals –Enhanced food production (fertilizers, herbicides, etc...) –Plastics and Polymers u Why Study Chemistry –Core requirement (?) –Central Science u Employment –Many fields Matter Chapt. 1.1 BIO Physics Medicine GEO Engr CHEM Law also: environmental economics electronics agriculture politics etc... S.U. B.S.

2 Chem 106, Prof. J.T. Spencer 2 Matter; A Review Chapt. 1.1 u Definition of Matter –anything that occupies space and has mass u States –gas (vapor); no fixed volume or shape, compressable –liquid; fixed volume no fixed shape, mostly incompressable –solid; fixed volume and shape, incompressable u Forms –Substances (pure or single); has a fixed composition and distinct properties. Most things encountered are mixtures of substances. u Properties –Physical Properties; can be measured without changing the substance, i.e., color, density, melting point, etc... –Chemical Properties; the way a substance changes (reacts), i.e., combustion

3 Chem 106, Prof. J.T. Spencer 3 Matter; A Review Chapt. 1.1 u Changes –Physical - Changes in appearance but not identity, i.e., evaporation, melting (all changes of state) –Chemical - transformation into a different substance Chemical ChangesPhysical Changes burning melting C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O H 2 O(s)H 2 O(l) C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O H 2 O(s)H 2 O(l) chemical reactionssublimation NaOH + HCl H 2 O + NaCl H 2 O(s)H 2 O(g) NaOH + HCl H 2 O + NaCl H 2 O(s)H 2 O(g) corrosiondissolution 4Fe + 3O 2 2 Fe 2 O 3 H 2 O(l ) + NaCl(s)NaCl(aq) 4Fe + 3O 2 2 Fe 2 O 3 H 2 O(l ) + NaCl(s)NaCl(aq)

4 Chem 106, Prof. J.T. Spencer 4 Matter; A Review Chapt. 1.1 u Mixtures; combinations of substances –Mixture –Mixture- –Homogeneous –Homogeneous – –Heterogeneous –Heterogeneous -

5 Chem 106, Prof. J.T. Spencer 5 Matter; A Review Chapt. 1.1 u Separating Mixtures using Physical Properties –How would you separate; Filtration Sand from Salt Filter Everyday Examples Everyday Examples; Auto Oil Filter Auto Air Filter Aquarium Water Filter Spaghetti Strainer Window Screens Registrar Flow

6 Chem 106, Prof. J.T. Spencer 6 Matter; A Review Chapt. 1.1 u Separating Mixtures using Physical Properties –How would you separate; Distillation Water from Salt Water NaCl(aq) NaCl(s) + H 2 O(l)

7 Chem 106, Prof. J.T. Spencer 7 Matter; A Review Chapt. 1.1 u Separating Mixtures using Physical Properties –How would you separate; Chromatograpgy Dyes from M&M’s BeforeAfter Dyes

8 Chem 106, Prof. J.T. Spencer 8 Salt and Sand Mixture Ink from Cabbage Juice solubility and filtration chromatography Water from Salt Water Iron and Gold Mixture distillationmagnetic properties melting point differences chem. reactivity (acids) Iodine from Copper Chloride solubility and filtration Matter; A Review Chapt. 1.1 u Separating Mixtures using Physical Properties –How would you separate;

9 Chem 106, Prof. J.T. Spencer 9 Matter; Elements and Compounds Chapt. 1.2 u Substances –Elements - substances which cannot be decomposed into simpler substances (see periodic table) –Compounds- substances which can be separated into two or more elements u Elements –110 Known (periodic table to be revisited) –make up all matter and composed of “subatomic particles” –symbols used for abbreviations (from older or common names) u Compounds –Elements combined in a definite proportion by mass (law of definite proportion) – properties different than consititutent elements Water; example of mixtures, compound and elements?

10 Chem 106, Prof. J.T. Spencer 10 Matter Matter Uniform ? HeterogeneousMixture Homogeneous Can be separated by physical methods Pure Substance Homogeneous Mixture (solution) Decomposed ? Compound Element Yes No No No Yes Yes

11 Chem 106, Prof. J.T. Spencer 11 Matter; Measurement Chapt. 1.3 u Systems –Metric - base 10 –SI- international scientific system –massKilogram –lengthMeter –timeSecond –electric currentAmpere –temperatureKelvin –lightCandela –AmountMole u Factor label method for conversions

12 Chem 106, Prof. J.T. Spencer 12 Matter; Measurement Chapt. 1.3 u Prefixes MegaM10 6 Kilok10 3 Decid10 -1 Centic10 -2 Millim10 -3 Micro  Nanon10 -9

13 Chem 106, Prof. J.T. Spencer 13 Matter; Measurement Chapt. 1.3 Common Units: 3Length and Mass 3Length - unit of distance measured in meters 3Mass - measures the amount of matter in an object in grams 3Temperature 3Kelvin 3Celsius°C = 5/9 (°F -32) K = °C

14 Chem 106, Prof. J.T. Spencer 14 Matter; Measurement Chapt. 1.3 Sample exercise: Ethylene glycol, the major ingredient in antifreeze, freezes at -11.5°C. What is the freezing point in a) K b) °F

15 Chem 106, Prof. J.T. Spencer 15 Matter; Measurement Chapt. 1.3 Derived Units: 3Volume 3Length x length x length 3measured in cm 3, which is equal to mL

16 Chem 106, Prof. J.T. Spencer 16 Matter; Measurement Chapt. 1.3 Derived Units: 3Density 3amount of mass per unit volume 3measured in g/cm 3, or g/mL

17 Chem 106, Prof. J.T. Spencer 17 Matter; Measurement Chapt. 1.3 Sample exercise: A student needs 15.0 g of ethanol (ethyl alcohol) for an experiment. If the density of the alcohol is g/mL, how many milliliters of alcohol are needed?

18 Chem 106, Prof. J.T. Spencer 18 Matter; Uncertainty in Measurement Chapt. 1.4 u Precision and Accuracy –Precision - how closely individual measurements agree –Accuracy- how closely the measurements agree with the true value u Significant Figures –All measurements are inaccurate intrinsically –measured quantities are reported such that the last figure is uncertain

19 Chem 106, Prof. J.T. Spencer 19 Matter; Uncertainty in Measurement Good Precision Poor Accuracy Good Precision Good Accuracy Poor Precision Poor Accuracy

20 Chem 106, Prof. J.T. Spencer 20 u Determining Significant Figures –all non zero digits are significant –zeros between nonzero digits are significant –zeros to the left of first nonzero digit are not significant –zeros at the end of a number and to the right of a decimal point are significant –when a number ends in a zero but with no decimal point, the zero may or may not be signigicant (use scientific notation) Matter; Uncertainty in Measurement Chapt. 1.4

21 Chem 106, Prof. J.T. Spencer 21 u Determining Significant Figures has 4 significant figures has 2 significant figures has 4 significant figures has 1 significant figures - multiplication and division; result can have no more than the figure with the fewest significant figures - addition and subtraction; result can have the same number of decimal places as the term with the least number of decimal places Matter; Uncertainty in Measurement Chapt. 1.4

22 Chem 106, Prof. J.T. Spencer 22 Matter; Uncertainty in Measurement Chapt. 1.3 Sample exercise: How many significant figures are in each of the following measurements? A) g B) 2.3 x 10 4 cm C) m 3

23 Chem 106, Prof. J.T. Spencer 23 Matter; Uncertainty in Measurement Chapt. 1.3 Sample exercise: How many significant figures are in each of the following measurements? A) g4 sig figs B) 2.3 x 10 4 cm C) m 3

24 Chem 106, Prof. J.T. Spencer 24 Matter; Uncertainty in Measurement Chapt. 1.3 Sample exercise: How many significant figures are in each of the following measurements? A) g4 sig figs B) 2.3 x 10 4 cm2 sig figs C) m 3

25 Chem 106, Prof. J.T. Spencer 25 Matter; Uncertainty in Measurement Chapt. 1.3 Sample exercise: How many significant figures are in each of the following measurements? A) g4 sig figs B) 2.3 x 10 4 cm2 sig figs C) m 3 3 sig figs

26 Chem 106, Prof. J.T. Spencer 26 Matter; Uncertainty in Measurement Chapt. 1.3 Sample exercise: There are exactly m in a mile. How many meters are in a distance of 1.35 mi?

27 Chem 106, Prof. J.T. Spencer 27 Matter; Uncertainty in Measurement Chapt. 1.3 Sample exercise: There are exactly m in a mile. How many meters are in a distance of 1.35 mi? 1.35 mi = 1 mi x m

28 Chem 106, Prof. J.T. Spencer 28 Matter; Uncertainty in Measurement Chapt. 1.3 Sample exercise: There are exactly m in a mile. How many meters are in a distance of 1.35 mi? 1.35 mi = 1 mi x m x = m

29 Chem 106, Prof. J.T. Spencer 29 Matter; Uncertainty in Measurement Chapt. 1.3 Sample exercise: There are exactly m in a mile. How many meters are in a distance of 1.35 mi? 1.35 mi = 1 mi x m 1.35 has 3 sig figs x = m has 7 sig figs 1 is infinitely significant

30 Chem 106, Prof. J.T. Spencer 30 Matter; Uncertainty in Measurement Chapt. 1.3 Sample exercise: There are exactly m in a mile. How many meters are in a distance of 1.35 mi? 1.35 mi = 1 mi x m 1.35 has 3 sig figs x = m has 7 sig figs x = 2170 m 1 is infinitely significant

31 Chem 106, Prof. J.T. Spencer 31 u Use Units throughout the calculation (helps “guide” calculation. u Should always yield the proper units u Uses conversion factors u Example; How fast is 50 mph in in/sec.? Dimensional Analysis 50 mi.1 hour5280 ft12 in. =in 1 hour3600 sec.1 mi.1 ftsec.

32 Chem 106, Prof. J.T. Spencer 32 Dimensional Analysis Chapt. 1.3 Sample exercise: By using a conversion factor from the back inside cover, determine the length in kilometers of a mi automobile race.

33 Chem 106, Prof. J.T. Spencer 33 Dimensional Analysis Chapt. 1.3 Sample exercise: By using a conversion factor from the back inside cover, determine the length in kilometers of a mi automobile race mi

34 Chem 106, Prof. J.T. Spencer 34 Dimensional Analysis Chapt. 1.3 Sample exercise: By using a conversion factor from the back inside cover, determine the length in kilometers of a mi automobile race mi 1 km mi

35 Chem 106, Prof. J.T. Spencer 35 Dimensional Analysis Chapt. 1.3 Sample exercise: By using a conversion factor from the back inside cover, determine the length in kilometers of a mi automobile race mi 1 km = km mi

36 Chem 106, Prof. J.T. Spencer 36 Dimensional Analysis Chapt. 1.3 Sample exercise: By using a conversion factor from the back inside cover, determine the length in kilometers of a mi automobile race mi 1 km = km mi * answer can only have 4 sig figs; km

37 Chem 106, Prof. J.T. Spencer 37 u Matter: Chemical and Physical Changes u Elements and Compounds u Units of Measurement u Uncertainty and Significant Figures u Precision and Accuracy u “Factor Label” Method (Dimensional Analysis) Chapter One; Review


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