Dr. Paul Charlesworth Michigan Technological University Dr. Paul Charlesworth Michigan Technological University C h a p t e rC h a p t e r C h a p t e rC h a p t e r Chemistry, 4 th Edition McMurry/Fay Chemistry, 4 th Edition McMurry/Fay 1 1 Matter and Measurement

2 Chemistry

3 Chemistry: The science of matter and the changes it can undergo Ira Remsen’s Reaction: “Nitric Acid acts upon Copper.”

4 Ira Remsen “A most costly experiment…”

5 Ira Remsen Cu(s) + 4HNO 3 (aq) → Cu(NO 3 ) 2 (aq) + 2NO 2 (g) + 2H 2 O(l)

6 Elements A substance that consists only of atoms with the same atomic number. Chemical Symbol: A collection of 1 or 2 letters used to represent an element. First chemical symbols were assigned by John Dalton in 1803 (no longer in use) Some modern chemical symbols: Hg, Zn, Mg

7 John Dalton

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9 John Dalton’s Symbols

10 John Dalton’s Symbols

11 Chemistry and the Elements

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14 Elements and the Periodic Table Periods: The seven horizontal rows that group elements based on their principal quantum number. Groups: The 18 vertical columns that group elements based on their angular momentum quantum number.

15 Elements and the Periodic Table Main Groups: s-block elements: Two groups on the left (1 & 2) p-block elements: Six groups on the right (13–18) Transition Metal Groups: d-block elements: Ten groups in the middle (3–12) f-block elements: Fourteen groups between 3 & 4 are called inner transition metals.

16 Elements and the Periodic Table

17 Elements and the Periodic Table

18 Elements

19 Elements

20 Elements

21 Elements

22 Elements

23 Properties of Matter Matter: anything that has both mass & volume. Properties: describe or identify matter. Intensive Properties do not depend on amount. Extensive Properties do depend on amount.

24 Physical Properties can be determined without changing the chemical makeup of the sample. Some typical physical properties are: Melting Point, Boiling Point, Density, Mass, Touch, Taste, Temperature, Size, Color, Hardness, Conductivity. Some typical physical changes are: Melting, Freezing, Boiling, Condensation, Evaporation, Dissolving, Stretching, Bending, Breaking. Properties of Matter

25 Chemical Properties are those that do change the chemical makeup of the sample. Some typical chemical properties are: Burning, Cooking, Rusting, Color change, Souring of milk, Ripening of fruit, Browning of apples, Taking a photograph, Digesting food. Note: Chemical properties are actually chemical changes. Properties of Matter

26 List of chemical changes possible. Description by senses – shape, color, odor, etc. Measurable properties – density, boiling point, etc. PROPERTIES Old substance destroyed. New substance formed. New form of old substance. No new substances formed. CHANGE CHEMICALPHYSICAL Properties of Matter

27 Properties of Matter

28 Properties of Matter Homogeneous matter has the same appearance, composition, and properties throughout. Heterogeneous matter has visibly different phases which can be seen, or properties that vary through the substance.

29 Pure substances have a distinct set of physical and chemical properties and cannot be separated by physical changes. A mixture is two or more pure substances that can be separated by physical changes. Properties of Matter

30 An element is a pure substance with its own set of physical and chemical properties that cannot be decomposed into simpler substances. A compound is a pure substance that can be decomposed by a chemical change into two or more pure substances. Properties of Matter

31 Matter Classification: Matter can be subdivided into mixtures and pure substances. Properties of Matter

32 Properties of Matter

33 Metals: Found on left side of periodic table. Nonmetals: Found on the right side of periodic table. Semimetals: Form a zigzag line at the boundary between metals and nonmetals. Properties of Matter

34 Which of the following represents a mixture? Properties of Matter

35 If the red spheres are oxygen and the white are hydrogen, which of the following represents (a) hydrogen peroxide, (b) hydroxide ions, and (c) a mixture of hydrogen and oxygen gas? Properties of Matter

36 Accuracy is how close to the true value a given measurement is. Precision is how well a number of independent measurements agree with one another. Accuracy, Precision, and Significant Figures in Measurement

37 Significant Figures are the total number of digits in the measurement. The results of calculations are only as reliable as the least precise measurement. Rules exist to govern the use of significant figures after the measurements have been made. Accuracy, Precision, and Significant Figures in Measurement

38 Mass of a Tennis Ball

39 Reading a Thermometer

40 Taking a Measurement

41 Taking a Measurement

42 Rules for Significant Figures: Zeros in the middle of a number are significant Zeros at the beginning of a number are not significant Zeros at the end of a number and following a period are significant Zeros at the end of a number and before a period may or may not be significant. Accuracy, Precision, and Significant Figures in Measurement

43 Rules for Rounding Numbers: If the first digit removed is less than 5 - round down If the first digit removed is greater than 5 - round up If the first digit removed is 5 and following numbers are nonzero - round up If the first digit removed is 5 and following numbers are zero - round down Accuracy, Precision, and Significant Figures in Measurement

44 How many significant figures does each of the following measurements have? (a) m(b) x 10 –3 g (c) 72,100 km(d) $25.03 Accuracy, Precision, and Significant Figures in Measurement

45 Round off each of the following measurements. (a) L to four significant figures (b) K to three significant figures (c) kg to four significant figures Accuracy, Precision, and Significant Figures in Measurement

46 Rules for Calculating Numbers: During multiplication or division, the answer can’t have more sig figs than any of the original numbers. During addition or subtraction, the answer can’t have more digits to the right of the decimal point than any of the original numbers. Accuracy, Precision, and Significant Figures in Measurement

47 Significant Figures in Calculations

48 Significant Figures in Calculations

49 Significant Figure Calculations Ok, now… Try These!