2Chemistry: A Science for the 21st Century Health and MedicineSanitation systemsSurgery with anesthesiaVaccines and antibioticsGene therapyEnergy and the EnvironmentFossil fuelsSolar energyNuclear energy
3Chemistry: A Science for the 21st Century Materials and TechnologyPolymers, ceramics, liquid crystalsRoom-temperature superconductors?Molecular computing?Food and AgricultureGenetically modified crops“Natural” pesticidesSpecialized fertilizers
5Qualitative data consists of general observations about the system The coffee is hotThe boy is tallQuantitative data comprises numbers obtained by various measurements of the system.The coffee is heated to 97°CJohn is 5 ft 6 in tall
6The scientific method is a systematic approach to research A hypothesis is a tentative explanation for a set of observationstested modified
7Force = mass x acceleration A law is a concise statement of a relationship between phenomena that is always the same under the same conditions.Force = mass x accelerationA theory is a unifying principle that explains a body of facts and/or those laws that are based on them.Atomic Theory
8Problem 1.3Classify the following statement as (a) qualitative (b) quantitative 1.The sun is approximately 93 million miles from earth. 2. Leonardo daVinci was a better painter than Michelangelo. 3.Ice is less dense than water. 4.Butter tastes better than margarine.
9Problem 1.4 (a)Classify the following statement as a (a) hypothesis (b) law (c) theory 1.Beethoven’s contribution to music would have been much greater if he had married. 2. An autumn leaf gravitates toward the ground because there is an attractive force between the leaf and the earth. 3. All matter is composed of very small particles called atoms
10Chemistry is the study of matter and the changes it undergoes Matter is anything that occupies space and has mass.A substance is a form of matter that has a definite composition and distinct properties.liquid nitrogengold ingotssilicon crystals
11Heterogeneous mixture – composition is not uniform throughout. A mixture is a combination of two or more substances in which the substances retain their distinct identities.Homogenous mixture – composition of the mixture is the same throughout.clear juice (apple, cranberry), bronze, solderHeterogeneous mixture – composition is not uniform throughout.cement,iron filings in sand
12Physical means can be used to separate a mixture into its pure components. distillationmagnet
13dry ice – carbon dioxide A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions.Compounds can only be separated into their pure components (elements) by chemical means.lithium fluoridequartzdry ice – carbon dioxide
14114 elements have been identified An element is a substance that cannot be separated into simpler substances by chemical means.114 elements have been identified82 elements occur naturally on Earthgold, aluminum, lead, oxygen, carbon, sulfur32 elements have been created by scientiststechnetium, americium, seaborgiumElement 118 discovered in 2006!
17Problem 1.16(a)Classify the following as a(n) (a) element (c) homogeneous mixture (b) compound (d) heterogeneous mixture filtered sea water Helium gas Kosher salt (sodium chloride) A bottle of soda (capped, unshaken) A milkshake Filtered air in a bottle concrete
19The Three States of Matter: Effect of a Hot Poker on a Block of Ice solidliquidgas
20Types of ChangesA physical change does not alter the composition or identity of a substance.ice meltingsugar dissolvingin waterA chemical change alters the composition or identity of the substance(s) involved.hydrogen burns in air to form water
21Problem 1.12(a)Does the following describe a (a) chemical change or a (b) physical change?The helium gas inside of a balloon tends to leak out after a few hours.Frozen orange juice is reconstituted by adding water to it.The growth of plants depends on the sun’s energy in a process called photosynthesis.A spoonful of table salt dissolves in a bowl of soup.
22Extensive and Intensive Properties An extensive property of a material depends upon how much matter is is being considered.masslengthvolumeAn intensive property of a material does not depend upon how much matter is is being considered.densitytemperaturecolor
23Interestingly, the process of measuring mass is called weighing! Matter - anything that occupies space and has mass.mass – measure of the quantity of matterSI unit of mass is the kilogram (kg)1 kg = 1000 g = 1 x 103 gweight – force that gravity exerts on an objectW = m x aSI unit of force is the Newton (N)1 N = 1 kg∙m/s2Interestingly, the process of measuring mass is called weighing!
24A 1 kg mass weighs almost 6 times more on earth than on the moon! Mass is constant, while weight is dependent on locationOn the moon, a = 1.67 m/s2W = m x a = 1 kg x 1.67 m/s21.67 NewtonOn earth, a = 9.81 m/s2W = 1 kg x 9.81 m/s2 = 9.81 kg∙m/s29.81 Newton9.81 Newton/1.67 Newton = 5.87A 1 kg mass weighs almost 6 times more on earth than on the moon!
31A Comparison of Temperature Scales 1KK = (0C C)1 0C273 K = 0 0C373 K = 100 0C0F = x 0C F9 0F5 0C32 0F = 0 0C212 0F = 100 0C
32Convert 327.5 0C to degrees Fahrenheit. Convert F to degrees Celsius.Convert 77 K, the boiling point of liquid nitrogen to degrees Celsius.
33Problem 1.24(a)Normally the human body can endure a temperature of 105 °F for only short periods of time without permanent damage to the brain and other vital organs. What is the temperature in °C?
34Problem 1.24(b)Ethylene glycol is a liquid organic compound that is used as an antifreeze in car radiators. It freezes at °C. Calculate the freezing point in °F.
35Problem 1.24(c)The temperature of the surface of the sun is about 6300 °C. What is this temperature is °F?
36Problem 1.24(d)The ignition temperature of paper is 451 °F. What is the temperature in K?
37Scientific Notation The number of atoms in 12 g of carbon: 602,200,000,000,000,000,000,0006.022 x 1023The mass of a single carbon atom in grams:1.99 x 10-23N x 10nN is a numberbetween 1 and 10n is a positive ornegative integer
38Scientific Notation Addition or Subtraction 568.762 0.00000772 move decimal leftmove decimal rightn > 0n < 0= x 102= 7.72 x 10-6Addition or SubtractionWrite each quantity with the same exponent nCombine N1 and N2The exponent, n, remains the same4.31 x x 103 =4.31 x x 104 =4.70 x 104
39Scientific Notation Multiplication Division (4.0 x 10-5) x (7.0 x 103) =(4.0 x 7.0) x (10-5+3) =28 x 10-2 =2.8 x 10-1Multiply N1 and N2Add exponents n1 and n2Division8.5 x 104 ÷ (5.0 x 109)=(8.5 ÷ 5.0) x =1.7 x 10-5Divide N1 and N2Subtract exponents n1 and n2
40Significant Figures Any digit that is not zero is significant 1.234 kg significant figuresZeros between nonzero digits are significant606 m significant figuresZeros to the left of the first nonzero digit are not significant0.08 L significant figureIf a number is greater than 1, then all zeros to the right of the decimal point are significant2.0 mg significant figuresIf a number is less than 1, then only the zeros that are at the end and in the middle of the number are significantg 3 significant figures
41How many significant figures are in each of the following measurements? 24 mL3001 gm36.4 x 104 molecules560 kg
42Problem 1.34How many significant figures are in each of the following measurements?0.006 Ldm60.5 mg605.5 cm2960 x 10-3 g6 kg60 m
43Significant Figures Addition or Subtraction The answer cannot have more digits to the right of the decimalpoint than any of the original numbers.89.3321.1+90.432one significant figure after decimal pointround off to 90.43.700.7867two significant figures after decimal pointround off to 0.79
44Significant Figures Multiplication or Division The number of significant figures in the result is set by the original number that has the smallest number of significant figures4.51 x == 16.53 sig figsround to3 sig figs6.8 ÷ == 0.0612 sig figsround to2 sig figs
45Significant Figures Exact Numbers Numbers from definitions or counted numbers of objects are considered to have an infinite number of significant figuresThe average of three measured lengths; 6.64, 6.68 and 6.70?3= = 6.67= 7Because 3 is an exact number
46Carry out the following arithmetic operations to the correct number of significant figures. 11,254.1 g g66.59 L – L8.16 m xkg ÷ 88.3 mL2.64x103 cm x102 cm
47Carry out the following arithmetic operations to the correct number of significant figures. 9.1 g – g7.1x104 dm x x102 dm6.54 g ÷ mL7.55x104 m – 8.62x103 m
48Problem 1.36Carry out the following operations as if they were calculations of experimental results, and express each answer in the correct units with the correct number of significant figures7.310 km ÷ 5.70 km(3.26 x 10-3 mg) – (7.88 x 10-5) mg(4.02 x 106 dm) + (7.74 x 107 dm)(7.8 m – 0.34 m)/(1.15 s s)
49Accuracy – how close a measurement is to the true value Precision – how close a set of measurements are to each otheraccurate&preciseprecisebutnot accuratenot accurate¬ precise
50Problem 1.38Three apprentice tailors (X,Y, and Z) are assigned to the task of measuring the seam of a pair of trousers. The results in inches are: X (31.5, 31.6, 31.4) Y (32.8, 32.3, 32.7) Z (31.9, 32.2, 32.1) The true length is 32.0 in. Comment on the precision and accuracy of each tailor’s measurements.
51Dimensional Analysis Method of Solving Problems Determine which unit conversion factor(s) are neededCarry units through calculationIf all units cancel except for the desired unit(s), then the problem was solved correctly.given quantity x conversion factor = desired quantitydesired unitgiven unitgiven unit x= desired unit
52Dimensional Analysis Method of Solving Problems How many mL are in 1.63 L?Conversion Unit 1 L = 1000 mL1L1000 mL1.63 L x= 1630 mL1L1000 mL1.63 L x=L2mL
53The speed of sound in air is about 343 m/s The speed of sound in air is about 343 m/s. What is this speed in miles per hour?conversion unitsmeters to milesseconds to hours1 mi = 1609 m1 min = 60 s1 hour = 60 min343msx1 mi1609 m60 s1 minx60 min1 hourx= 767mihour
54Problem 1.46The current speed limit in some states in the US is 55 miles per hour. What is the speed limit in km/hr? (1 mi = 1609 m)
55Problem 1.66Vanillin is the substance whose aroma the human nose detects in the smallest amount. The threshold limit is 2.0 x 10-11g per liter of air. If the current price of 50 g of vanillin is $112, determine the cost (in cents) to supply enough vanillin so that the aroma could be detected in a large aircraft hanger with a volume of 5.0 x 107 ft3