1. Section 1 Chemistry and Measurements

2. 2 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. What Is Chemistry? Chemistry is the study of the composition, structure, and properties of matter and energy and changes that matter undergoes. –Matter is anything that occupies space and has mass. Atoms – are the smallest units that we associate with the chemical behavior of matter. Mass – is a measure of the quantity of matter that an object contains (does not vary with location). –Energy is the “ability to do work.” Forms of energy Potential energy – energy of position or arrangement (composition) – “stored energy” Kinetic energy – energy of motion

3. 3 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Types of energy Work Heat Specific heat of a substance is the amount of heat required to raise the temp of 1 g substance by 1 o C. water – 1.00 cal or 4.182 J g o C g o C heat absorbed or release = mass x sp heat x  T How much heat in calories does it take to raise the temp of 225 g water from 25.0 o C to 100.0 o C?

4. 4 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Experiment and Explanation Experiment and explanation are the heart of chemical research. –An experiment is the observation of facts or events that can be described scientifically and were carried out in a controlled manner so that the results can be duplicated and rational conclusions obtained. –After a series of experiments, a researcher may see some relationship or regularity in the results.

5. 5 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Experiment and Explanation If the regularity or relationship is fundamental and we can state it simply, we call it a law. –A law is a concise statement or mathematical equation about a fundamental relationship or regularity of nature. –An example is the law of conservation of mass, which says that mass, or quantity of matter, remains constant during any chemical change (mass starting material = mass ending material).

6. 6 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Experiment and Explanation Explanations help us organize knowledge and predict future events. –A hypothesis is a tentative explanation of some regularity of nature. –If a hypothesis successfully passes many tests, it becomes known as a theory. –A theory is a tested explanation of some regularity of nature.

7. 7 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Experiment and Explanation Scientific Method - the general process of advancing scientific knowledge through observation, laws, hypotheses, or theories.

8. 8 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. A representation of the scientific method.

9. 9 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Matter: Physical State and Chemical Constitution There are two principal ways of classifying matter: –By its physical state as a solid, liquid, or gas. –By its chemical constitution as an element, compound, or mixture.

10. 10 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Solids, Liquids, and Gases Solid: the form of matter characterized by rigidity; a solid is relatively incompressible and has a fixed shape and volume. Gas: the form of matter that is an easily compressible fluid; a given quantity of gas will fit into a container of almost any size and shape. Liquid: the form of matter that is a relatively incompressible fluid; liquid has a fixed volume but no fixed shape.

11. 11 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Elements, Compounds, and Mixtures Physical change is a change in the form of matter but not in its chemical identity. –Physical changes are usually reversible. –No new compounds are formed during a physical change. –Melting ice is an example of a physical change. –Species retain their chemical identities and can be separated by some physical means.

12. 12 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Chemical change, or chemical reaction, is a change in which one or more kinds of matter are transformed into a new kind of matter or several new kinds of matter. –Chemical changes are usually irreversible by physical means (can do by chemical means). –New compounds are formed during a chemical change. –The rusting of iron is an example of a chemical change. Substance – is a kind of matter that cannot be separated into other kinds of matter by any physical process. Mixture – is a material that can be separated by physical means into two or more substances Salt (NaCl) in water Fe (s) + O 2 (g)  Fe 2 O 3 (s), rust

13. 13 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. A physical property is a characteristic that can be observed for material without changing its chemical identity. Examples are physical state of substance (solid, liquid,or gas), melting point, and color. A chemical property is a characteristic of a material involving its chemical change. –A chemical property of iron is its ability to react with oxygen to produce rust. Elements, Compounds, and Mixtures (cont’d)

14. 14 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Millions of substances have been characterized by chemists. Of these, a very small number are known as elements, from which all other substances are made. –An element is a substance that cannot be decomposed by any chemical reaction into simpler substances. –The smallest unit of an element is the atom. Elements, Compounds, and Mixtures (cont’d)

15. 15 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Most substances are compounds. –A compound is a substance composed of two or more elements chemically combined. –The smallest unit of a compound is the molecule. –The law of definite proportions states that a pure compound, whatever its source, always contains definite or constant proportions of the elements by mass. Elements, Compounds, and Mixtures (cont’d)

16. 16 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. heterogeneous “distinct parts” homogeneous “uniform” Atoms  elements  molecules  compounds  substances pure “definite proportions” mixture “variable proportions” Most of the materials we see around us are mixtures. –A mixture is a material that can be separated by physical means into two or more substances. –Unlike a pure compound, a mixture has variable composition. –Mixtures are classified as heterogeneous (“coarse mixture”) if they consist of physically distinct parts or homogeneous (“solutions”) when the properties are uniform throughout. Elements, Compounds, and Mixtures HW 1

17. 17 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Chemical symbol is a one or two letter designation derived from the name of an element (based on English or Latin name). First letter of symbol is capitalized and second is always lower case. Co vs CO Compounds are designated by combination of chemical symbols called formula.

18. 18 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Measurement and Significant Figures Measurement is the comparison of a physical quantity to be measured with a unit of measurement -- that is, with a fixed standard of measurement. –The term precision refers to the closeness of the set of values obtained from identical measurements of a quantity (reproducibility). –Accuracy refers to the closeness of a single measurements to its true value (truthfulness of data).

19. 19 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. To indicate the precision of a measured number (or result of calculations on measured numbers), we often use the concept of significant figures. –Significant figures are those digits in a measured number (or result of the calculation with a measured number) that include all certain digits plus a final one having some uncertainty (first digit basically guessing).

20. 20 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Rules for Significant Figures: –All nonzero digits are significant. i.e. 1111286 –Zeros between significant figures are significant. i.e. 100120,006 –Zeros preceding the first nonzero digit are not significant. i.e. 0.00020.00206 –Zeros to the right of the decimal after a nonzero digit are significant. i.e. 0.003009.009.1090.0 –Zeros at the end of a nondecimal number may or may not be significant. (Use scientific notation.) i.e. 900900.

21. 21 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Scientific notation – is the representation of a number in the form A. x 10 n, where A is a number (sign digits only) with a single nonzero digit to the left of the decimal point and n is an integer or whole number. 900 300,000,000 0.0000301 843.4 0.00421 6.39 x 10 -4 3.275 x 10 2 Note: exp or EE represents “x 10” HW 2-3

22. 22 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Number of significant figures refers to the number of digits reported for the value of a measured or calculated quantity, indicating the precision of the value. [Basically means if all quantities have X sign fig can’t report final answer with more than X sign figs: measurement or calculation dictates sign figs.] –When multiplying and dividing measured quantities, give as many significant figures as the least found in the measurements used. 2.1 x 3.52 = 7.392 = 7.4 –Which gets us to rounding: left most digit to be dropped – 5 or greater add 1 to last digit to be retained, less than five leave alone – 1.2143 -- 1.21 –Multiple step calculation - Guard digit: 1.214 –When adding or subtracting measured quantities, give the same number of decimals as the least found in the measurements used. 84.2 (3 sign) +22.321 (5 sign) 106.521 106.5(4 sign) arithmetic rules if combined ( ), x /, + -

23. 23 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. 3.38 – 3.012 = 0.368 = 0.37 2.4 x 10 -3 + 3.56 x 10 -1 = 0.0024 +0.356 0.3584 = 3.58 x 10 -1 2.568 x 5.8 = 14.8944 = 3.55814 = 3.6 4.186 4.186 or 14.9 gives 3.55948 4.18 – 58.16 x (3.38 – 3.01) = 4.18 – 58.16 x (0.37) = 4.18 – 21.5192 = -17.3392 = -17 6.3 + 7.2 = 0.5256 13.5 = 25.685 = 25.7 0.5256 HW 4

24. 24 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. An exact number is a number that arises when you count items or when you define a unit. –For example, when you say you have nine coins in a bottle, you mean exactly nine. –When you say there are twelve inches in a foot, you mean exactly twelve. –Note that exact numbers have no effect on significant figures in a calculation. Measurement and Significant Figures (cont’d)

25. 25 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. SI Units and SI Prefixes In 1960, the General Conference of Weights and Measures adopted the International System of units (or SI), which is a particular choice of metric units. –This system has seven SI base units, the SI units from which all others can be derived.

26. 26 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Table SI Base Units QuantityUnitSymbol LengthMeterm MassKilogramkg TimeSeconds TemperatureKelvinK Amount of substanceMolemol Electric currentAmpereA Luminous intensityCandelacd

27. 27 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. SI Units and SI Prefixes The advantage of the metric system is that it is a decimal system. –A larger or smaller unit is indicated by a SI prefix -- that is, a prefix used in the International System to indicate a power of 10. –The next slide shows SI prefixes most commonly used.

28. 28 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Table SI Prefixes MultiplePrefixSymbol 1 x 10 6 megaM 1 x 10 3 kilok 1 x 10 -1 decid 1 x 10 -2 centic 1 x 10 -3 millim 1 x 10 -6 micro  1 x 10 -9 nanon 1 x 10 -12 picop

29. 29 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Ex.9.7 x 10 3 m  km 7.85 x 10 -2 g  cg 1.6 x 10 6 mm  Mm HW 5

30. 30 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Temperature The Celsius scale (formerly the Centigrade scale) is the temperature scale in general scientific use. –However, the SI base unit of temperature is the kelvin (K), a unit based on the absolute temperature scale. –The conversion from Celsius to Kelvin is simple since the two scales are simply offset by 273.15 o (1K change = 1 o C change).

31. 31 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Temperature The Fahrenheit scale is at present the common temperature scale in the United States. –The conversion of Fahrenheit to Celsius (1.8 o F change = 1 o C change)., and vice versa, can be accomplished with the following formulas.

32. 32 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Ex.102.5 o F  o C and K -78 o C  K and o F HW 6

33. 33 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Derived Units The SI unit for speed is meters per second, or m/s. –This is an example of an SI derived unit, created by combining SI base units. –Volume is defined as length cubed and has an SI derived unit of cubic meters (m 3 ). –Traditionally, chemists have used the liter (L), which is a unit of volume equal to one cubic decimeter.

34. 34 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. where d is the density, m is the mass, and V is the volume. Generally the unit of mass is the gram. The unit of volume is the mL for liquids; cm 3 for solids; and L for gases. Specific gravity of substance = density of substance @T density of water Derived Units The density of an object is its mass per unit volume,

35. 35 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. A Density Example A sample of the mineral galena (lead sulfide) weighs 12.4 g and has a volume of 1.64 cm 3. What is the density of galena?

36. 36 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Ethanol has a density of 0.789 g/mL. What volume of ethanol must be poured into a graduated cylinder to equal 30.3 g? HW 7

37. 37 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Units: Dimensional Analysis In performing numerical calculations, it is good practice to associate units with each quantity. –The advantage of this approach is that the units for the answer will come out of the calculation. –And, if you make an error in arranging factors in the calculation, it will be apparent because the final units will be nonsense.

38. 38 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Units: Dimensional Analysis Dimensional analysis (or the factor-label method) is the method of calculation in which one carries along the units for quantities. –Suppose you simply wish to convert 20 yards to feet. –Note that the units have cancelled properly to give the final unit of feet.

39. 39 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Units: Dimensional Analysis The ratio (3 feet/1 yard) is called a conversion factor. –The conversion-factor method may be used to convert any unit to another, provided a conversion equation exists.

40. 40 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Relationships of Some U.S. and Metric Units LengthMassVolume 1 in = 2.54 cm1 lb = 454 g1 qt = 0.9464 L 1 yd = 0.9144 m1 lb = 16 oz4 qt = 1 gal 1 mi = 1.609 km1 oz = 28.35 g 1 mi = 5280 ft

41. 41 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. How many meters are in 6.81 miles? HW 8

42. 42 Material was developed by combining Janusa’s material with the lecture outline provided with Ebbing, D. D.; Gammon, S. D. General Chemistry, 8th ed., Houghton Mifflin, New York, NY, 2005. Majority of figures/tables are from the Ebbing lecture outline. Unit Conversion (prefixes) How many mg of sodium hydrogen carbonate are in 55.0 mL of a solution that contains 3.48 g/L of sodium hydrogen carbonate? 3.48 g 1 L 55.0 mL = 191 mg X