CH104 CHEMISTRY FOR ALLIED HEALTH CHEMEKETA COMMUNITY COLLEGE INSTRUCTOR: Dr. Jan Cammack http://faculty.chemeketa.edu/jcammack/

1st Day Stuff Who are you? Are you in the right place? GOB Chemeketa elearn site Course Web Page Course Syllabus & requirements Who am I? Web CT Quizzes

CH104 Recitation & Lab: Week 1 Read through Lab 0: Safety and Lab Experiment 1: The Scientific Method Homework problems will be due each week at recitation Week 1 problems and online quiz due Tuesday

What is Chemistry The Scientific Method How To Study

Definition of Chemistry Chemistry is the study of substances in terms of Composition What is it made of? Structure How is it put together? Properties What characteristics does it have? Reactions How does it behave with other substances?

Major divisions of Chemistry General Inorganic Analytical Physical Organic Biochemistry Elements besides Carbon Methods of analysis Theory and concepts Carbon based compounds Chemistry of living things

Scientific Method: Thinking like a Scientist Chemistry in Our Lives Scientific Method: Thinking like a Scientist

The Scientific Method Process used by scientists to explain observations. It involves making observations writing a hypothesis doing experiments proposing a theory

Scientific method Observe: Take notice Hypothesize:Form an educated guess to explain your observation. Test the guess: Design an experiment. Reject or confirm the hypothesis Modify the guess or test if needed. Conclude (Propose a Theory):

Scientific method ? Try new tests No Observe Question Hypothesis Experiment Try new tests No Did it work? Yes Develop a theory Do more experiments

Summary of the Scientific Method

Everyday Scientific Thinking The sound from a CD in a CD player skips. Observation: The CD player is faulty. Hypothesis 1: Experiment 1: When the CD is replaced with another one, the sound from the 2nd CD is OK. Hypothesis 2: The original CD has a defect. Experiment 2: When I play the CD in another player, the sound still skips. Theory: My experimental results indicate that the original CD has a defect.

Learning Check The step of scientific method indicated in the processes below is 1) observation 2) hypothesis 3) experiment 4) theory A. A blender does not work when plugged in. B. The blender motor is broken. C. The plug has malfunctioned. D. The blender does not work when plugged into a different outlet. E. The blender needs repair.

Solution The step of scientific method indicated in the processes below is 1) observation 2) hypothesis 3) experiment 4) theory A. A blender does not work when plugged in. 1 B. The blender motor is broken. 2 C. The plug has malfunctioned. 2 D. The blender does not work when plugged into a different outlet. 3 E. The blender needs repair. 4

A Study Plan for Learning Chemistry Chemistry in Our Lives A Study Plan for Learning Chemistry

Text Features for Learning The study features in the text include: Learning Goals indicate what to learn Concept Checks develop new concepts Sample Problems provide step-by-step problem solving models Guides to Problem Solving give directions for working out a problem

Studying for Chemistry Activities that can help you learn chemistry successfully include the following: attend class regularly go to your instructor’s office hours form a study group with other students to discuss problems and their solutions study and work problems every day do not wait until the night before the test to prepare for an exam

Active Learning Active participation will help learn the material more quickly and with more understanding. Obtain an overview from the Looking Ahead topics. Form a question from the section title. Read the section, and answer your question. Work the Sample Problems and Study Checks. Check Answers at the end of the chapter. Proceed to the next section in the text and repeat above.

Learning Check Which of the following activities would be part of a successful study plan? A. staying out late the night before an exam B. reading the text before class C. working problems with a study group D. skipping the lecture 1 or 2 times a week E. discussing a problem with the instructor

Solution Which of the following activities would be part of a successful study plan? A. (No) staying out late the night before an exam B. (Yes) reading the text before class C. (Yes) working problems with a study group D. (No) skipping lecture 1 or 2 times a week E. (Yes) discussing a problem with the instructor

Conversion Calculations Chapter 1: Measurement Units of Measurement Scientific Notation Significant Figures Conversion Calculations Density

Chapter 1 Measurements 1.1 Units of Measurement

Measurements in chemistry Units are important has little meaning, just a number 45,000 has some meaning - money $45,000 more meaning - person’s salary $45,000/yr

Measurements in chemistry English units. Still commonly used in daily life. For Example: Common English measures of volume 1 tablespoon = 3 teaspoons 1 cup = 16 tablespoons 1 pint = 2 cups 1 quart = 2 pints 1 gallon = 4 quarts 1 peck = 2 gallons 1 bushel = 4 pecks Not often used in scientific work

Units of Measurement Metric SI Common Conversions Length meter (m) meter (m) 1 m = 100 cm = 1000 mm 1 m = 1.09 yd 2.54 cm = 1 in

Units of Measurement Metric SI Common Conversions Length Volume meter (m) meter (m) 1 m = 100 cm = 1000 mm 1 m = 1.09 yd 2.54 cm = 1 in liter (L) cubic meter (m3) 1 L = 1000 mL 1 L = 1.06 qt 946 mL = 1 qt

Units of Measurement Metric SI Common Conversions Length Volume Mass meter (m) meter (m) 1 m = 100 cm = 1000 mm 1 m = 1.09 yd 2.54 cm = 1 in liter (L) cubic meter (m3) 1 L = 1000 mL 1 L = 1.06 qt 946 mL = 1 qt gram (g) Kilogram (kg) 1 kg = 1000 g 1 kg = 2.20 lb 454 g = 1 lb

Mass: Mass Vs. Weight Weight: The amount of material in an object Mass (in g’s) of a 1L Bowling Ball > a 1 L Balloon Weight: Pull of Gravity on an object. Weight of Person on Earth > Person on Moon Matter: The stuff things are made of. Has Mass and takes up space. Mass: The amount of stuff. Usually measured in grams. Bowling ball has more mass than Weight on earth.

How much would you weigh Mass Vs. Weight How much would you weigh on another planet? http://www.exploratorium.edu/ronh/weight/

Units of Measurement Metric SI Common Conversions Length Volume Mass Time Temp meter (m) meter (m) 1 m = 1.09 yd 2.54 cm = 1 in liter (L) cubic meter (m3) 1 L = 1.06 qt 946 mL = 1 qt gram (g) Kilogram (kg) 1 kg = 2.20 lb second (s) second (s) 60 s = 1 min Celsius (oC) Kelvin (K) oC = (oF-32)/1.8 K = oC + 273

Learning Check 1) length, 2) mass, or 3) volume. For each of the following, indicate whether the unit describes 1) length, 2) mass, or 3) volume. ____ A. A bag of tomatoes is 4.5 kg. ____ B. A person is 2.0 m tall. ____ C. A medication contains 0.50 g of aspirin. ____ D. A bottle contains 1.5 L of water.

Solution 2 1 2 3 1) length, 2) mass, or 3) volume. For each of the following, indicate whether the unit describes 1) length, 2) mass, or 3) volume. ____ A. A bag of tomatoes is 4.5 kg. ____ B. A person is 2.0 m tall. ____ C. A medication contains 0.50 g of aspirin. ____ D. A bottle contains 1.5 L of water. 2 1 2 3

Learning Check Identify the measurement that has an SI unit. A. John’s height is _____. 1) 1.5 yd 2) 6 ft 3) 2.1 m B. The race was won in _____. 1) 19.6 s 2) 14.2 min 3) 3.5 h C. The mass of a lemon is _____. 1) 12 oz 2) 0.145 kg 3) 0.62 lb D. The temperature is _____. 1) 85 °C 2) 255 K 3) 45 °F

Solution Identify the measurement that has an SI unit. A. John’s height is _____. 1) 1.5 yd 2) 6 ft 3) 2.1 m B. The race was won in _____. 1) 19.6 s 2) 14.2 min 3) 3.5 h C. The mass of a lemon is _____. 1) 12 oz 2) 0.145 kg 3) 0.62 lb D. The temperature is _____. 1) 85 °C 2) 255 K 3) 45 °F

Chapter 1 Measurements 1.2 Scientific Notation

Scientific notation If a number is larger than 1 Move decimal point X places left to get a number between 1 and 10. 1 2 3 , 0 0 0 , 0 0 0. = 1.23 x 108 The resulting number is multiplied by 10X.

If a number is smaller than 1 Scientific notation If a number is smaller than 1 Move decimal point X places right to get a number between 1 and 10. 0. 0 0 0 0 0 0 1 2 3 = 1.23 x 10-7 The resulting number is multiplied by 10-X.

Examples Write in Scientific Notation: 25 = 8931.5 = 0.000593 = 0.0000004 = 3,210. = 2.5 x 10 1 8.9315 x 10 3 5.93 x 10 - 4 4 x 10 - 7 3.210 x 103

Scientific notation 1.44939 x 10-2 = 0.0144939 On Calculator 1.44939 (-) 2 EE 1.44939 E-2 x 10 Means x 10 Change Sign

Practice: Scientific Notation Write 4.2 x 103 in regular numerical format. 4200 Write 35,500 in scientific notation. 3.55 x 104 Write 6.830 x 10-2 in regular format. 0.06830 Write 0.00096 in scientific notation. 9.6 x 10-4

Learning Check Select the correct scientific notation for each. A. 0.000 000 08 m 1) 8 x 108 m 2) 8 x 10-8 m 3) 0.8 x 10-7 m B. 72 000 L 1) 7.2 x 104 L 2) 72 x 103 L 3) 7.2 x 10-4

Solution Select the correct scientific notation for each. A. 0.000 000 08 m 1) 8 x 108 m 2) 8 x 10-8 m 3) 0.8 x 10-7 m B. 72 000 L 1) 7.2 x 104 L 2) 72 x 103 L 3) 7.2 x 10-4

Learning Check Write each as a standard number. A. 2.0 x 10-2 s 1) 200 s 2) 0.0020 s 3) 0.020 s B. 1.8 x 105 g 1) 180 000 g 2) 0.000 018 g 3) 18 000 g

Solution Write each as a standard number. A. 2.0 x 10-2 s 1) 200 s 2) 0.0020 s 3) 0.020 s B. 1.8 x 105 g 1) 180 000 g 2) 0.000 018 g 3) 18 000 g

Review: Exponents Multiplication Add Exponents (10X )( 10Y) = 10X+Y (102 )( 103) = 102+3 = 105 (10)(10) (10)(10)(10) = 100,000 1 - 47 1997, West Educational Publishing.

Review: Exponents Division (103) Subtract Exponents (10Y) (10X) = 10X-Y (10Y) (102) = 102-(3) = 10-1 (103) (10)(10) = 1 = 10-1 = 0.1 (10)(10)(10) (10)

1.3 Measured Numbers and Significant Figures Chapter 1 Measurements 1.3 Measured Numbers and Significant Figures

Measured & Exact Numbers from counting or by definition 12 coins per package 12 coins 1 package 1 package 12 coins = 12 coins 1 dozen coins 1 dozen coins 12 coins =

Examples of Exact Numbers when objects are counted from numbers in a defined relationship

Measured & Exact Numbers Measured Numbers = estimated using a tool All measurements contain some uncertainty. We make errors Tools have limits

Accuracy Precision Consistency How close are we to the true value? Truth How well do our values agree? Consistency

Accuracy and precision Our goal! Truth and Consistency Values we can trust.

Length of object is between 6.7 and 6.8 Significant figures Length of object is between 6.7 and 6.8 The next digit would be a guess.             If use 6.76 then have error of + 0.01cm and have 3 significant figures.

Significant figures Expresses accuracy & precision. You can’t report values more accurate than the methods of measurement used . 6.76 units = 3 significant figures Certain Digits Uncertain Digit

Learning Check . l8. . . . l . . . . l9. . . . l . . . . l10. . cm What is the length of the red line? 1) 9.0 cm 2) 9.03 cm 3) 9.04 cm

Solution The length of the red line could be reported as 2) 9.03 cm or 3) 9.04 cm The estimated digit may be slightly different. Both readings are acceptable. . l8. . . . l . . . . l9. . . . l . . . . l10. . cm

Meniscus is between 8.4 and 8.5 The next digit would be a guess. Significant figures Meniscus is between 8.4 and 8.5 The next digit would be a guess. We can estimate the value to be 8.45 mL but cannot be more accurate than that. 8.45 has 3 sig figs.

Significant figures 3 Sig Figs Sig Figs don’t depend on the decimal point. 255 millimeters 25.5 centimeters 2.55 decimeters 0.255 meters 0.0255 decameters 3 Sig Figs

Significant figures: Rules for zeros Leading zeros are not significant. 0.00421 3 sig figs Leading zero Captive zeros are significant. 4012 4 sig figs Captive zero Trailing zeros behind decimal are significant. 114.20 5 sig figs Trailing zero

Significant figures: Rules for zeros 32,000 Are the 0’s significant? 2 sig figs = 3 sig figs = 4 sig figs = 5 sig figs = 3.2 x 104 3.20 x 104 3.200 x 104 3.2000 x 104 32,000.

Significant figures: Rules for zeros 1025 km 2.00 mg 0.00570 520 Four (Captive zeros are significant) Three (trailing zeros behind decimal are significant) Three (only trailing zero behind decimal is significant, leading zeros are not) Two (No decimal, zero assumed insignif)

Significant Figures in Scientific Notation All digits, including zeros in the coefficient, are significant. Scientific Notation Number of Significant Figures___________ 8 x 104 m 8.0 x 104 m 8.00 x 104 m 1 2 3

Learning Check State the number of significant figures in each of the following measurements: A. 0.030 m B. 4.050 L C. 0.0008 g D. 2.80 m

Solution State the number of significant figures in each of the following measurements: A. 0.030 m B. 4.050 L C. 0.0008 g D. 2.80 m 2 4 1 3

Learning Check A. Which answer(s) contains 3 significant figures? 1) 0.4760 2) 0.00476 3) 4.76 x 103 B. All the zeros are significant in 1) 0.00307 2) 25.300 3) 2.050 x 103 C. The number of significant figures in 5.80 x 102 is 1) one 3) two 3) three

Solution A. Which answer(s) contains 3 significant figures? 1) 0.4760 2) 0.00476 3) 4.76 x 103 B. All the zeros are significant in 1) 0.00307 2) 25.300 3) 2.050 x 103 C. The number of significant figures in 5.80 x 102 is 1) one 3) two 3) three

Learning Check In which set(s) do both numbers contain the same number of significant figures? 1) 22.0 and 22.00 2) 400.0 and 4.00 x 102 3) 0.000015 and 150 000

Both numbers contain two (2) significant figures. Solution In which set(s) do both numbers contain the same number of significant figures? 1) 22.0 and 22.00 2) 400.0 and 4.00 x 102 3) 0.000015 and 150 000 Both numbers contain two (2) significant figures.

Learning Check 1. using a measuring tool 2. counting 3. definition A. Exact numbers are obtained by 1. using a measuring tool 2. counting 3. definition B. Measured numbers are obtained by

Solution 1. using a measuring tool 2. counting 3. definition A. Exact numbers are obtained by 1. using a measuring tool 2. counting 3. definition B. Measured numbers are obtained by

Learning Check Classify each of the following as exact (E) or measured (M) numbers. Explain your answer. A. __ Gold melts at 1064 °C. B. __ 1 yard = 3 feet C. __ The diameter of a red blood cell is 6 x 10-4 cm. D. __ There are 6 hats on the shelf. E. __ A can of soda contains 355 mL of soda.

Solution M E M E M Classify each of the following as exact (E) or measured (M) numbers. Explain your answer. A. __ Gold melts at 1064 °C. B. __ 1 yard = 3 feet C. __ The diameter of a red blood cell is 6 x 10-4 cm. D. __ There are 6 hats on the shelf. E. __ A can of soda contains 355 mL of soda. M E M E M

1.4 Significant Figures in Calculations Chapter 1 Measurements 1.4 Significant Figures in Calculations

1st insignificant digit Rounding Sometimes a calculated answer shows too many significant digits so we need to round. Write with 4 Significant Figures: 2.579 035 5 becomes 2.580 > 5 round up < 5 round down. 1st insignificant digit 4 34.20 221 becomes 34.20

Adding Significant Zeros Sometimes a calculated answer requires more significant digits so we need to add zeros. Zeros added to give 3 significant figures Calculated answer 4 1.5 0.2 12 4.00 1.50 0.200 12.0

Learning Check Adjust the following calculated answers to give answers with three significant figures. A. 824.75 cm B. 0.112486 g C. 8.2 L

Solution Adjust the following calculated answers to give answers with three significant figures. A. 824.75 cm B. 0.112486 g C. 8.2 L First digit dropped is greater than 4. 825 cm 0.112 g First digit dropped is 4. 8.20 L Significant zero is added.

Significant figures and calculations An answer can’t have greater significance than the quantities used to produce it. Example How fast did you run if you went 1.00 km in 3.0 minutes? 0.3333333333 speed = 1.00 km 3.0 min = ?

Simplified rules for significant figures Multiplication & Division Problems: Do calculations. speed = 1.00 km 3.0 min = 0.333333333 km min 3 sig figs Look at sig figs for each value in calculation. (Constants don’t count.) 2 sig figs Report answer with same sig figs as least significant value. = 0.33 km min Round off as needed.

Practice: Significant Figures in Calculations The measurement containing the fewest significant figures determines the number of significant figures in the answer. Example 1: 2.8 m x 0.2 m = 0.56 = 0.6 m2 Example 2: 252 mi / 3.2 hr = 78.75 = 79 mi/hr

Simplified rules for significant figures Addition & Subtraction Problems: Do calculations. Significant to .1 1.9 + 18.65 20.55 Significant to .01 Look at least significant place for each value in calculation. Report answer to least significant place. = 20.6 Round off as needed. Significant to .1

Add & Sub mixed w/ Mult & Div Problems: Do Addition & Subtraction calculations 1st. 3 sig figs (after addition) (1.9 + 18.65 ) = 2.153 ( 20.55 ) = 2.153 4 sig figs Make note of the least significant place.

Add & Sub mixed w/ Mult & Div Problems: Do Multiplication & Division calculations. 3 sig figs (after addition) (1.9 + 18.65 ) = 2.153 ( 20.55 ) = 2.153 9.54482118 4 sig figs 9.54 Round to least # sig fig.

Learning Check Give an answer for the following with the correct number of significant figures: A. 2.19 x 4.2 = 1) 9 2) 9.2 3) 9.198 B. 4.311 ÷ 0.07 = 1) 61.59 2) 62 3) 60 C. 2.54 x 0.0028 = 0.0105 x 0.060 1) 11.3 2) 11 3) 0.041

Solution Give an answer for the following with the correct number of significant figures: A. 2.19 x 4.2 = 1) 9 2) 9.2 3) 9.198 B. 4.311 ÷ 0.07 = 1) 61.59 2) 62 3) 60 C. 2.54 x 0.0028 = 0.0105 x 0.060 1) 11.3 2) 11 3) 0.041 2.54 x 0.0028  0.0105  0.060 = = 11.28888889 = 11 (rounded)

Learning Check For each calculation, round the answer to give the correct number of decimal places. A. 235.05 + 19.6 + 2 = 1) 257 2) 256.7 3) 256.65 B. 58.925 – 18.2 = 1) 40.725 2) 40.73 3) 40.7

Solution For each calculation, round the answer to give the correct number of decimal places. A. 235.05 + 19.6 + 2 = 1) 257 2) 256.7 3) 256.65 B. 58.925 – 18.2 = 1) 40.725 2) 40.73 3) 40.7 235.05 +19.6 + 2 256.65 rounds to 257 58.925 –18.2 40.725 rounds to 40.7

1.5 Prefixes and Equalities Chapter 1 Measurements 1.5 Prefixes and Equalities

Prefixes A prefix in front of a unit increases or decreases the size of that unit by one or more factors of 10 indicates a numerical value Prefix Value 1 kilometer = 1000 meters 1 kilogram = 1000 grams

Metric prefixes 1,000 = (103) 1km = 1,000 m 0.1 = (10-1) 1m = 10 dm Prefix (Symbol) Factor (multiple) Common Conversion mega (M) kilo (k) deci (d) centi (c) milli (m) micro (m) nano (n) 1,000,000 = (106) 1Mm = 1,000,000 m 1,000 = (103) 1km = 1,000 m 0.1 = (10-1) 1m = 10 dm 0.01 = (10-2) 1m = 100 cm 0.001 = (10-3) 1m = 1,000 mm 0.000001 = (10-6) 1m = 1,000,000 mm 0.000,000,001 = (10-9) 1m = 1,000,000,000 nm

Metric and SI Prefixes

Metric and SI Prefixes (continued)

Learning Check Indicate the unit that matches the description: 1. a mass that is 1000 times greater than 1 gram 1) kilogram 2) milligram 3) megagram 2. a length that is 1/100 of 1 meter 1) decimeter 2) centimeter 3) millimeter 3. a unit of time that is 1/1000 of a second 1) nanosecond 2) microsecond 3) millisecond

Solution Indicate the unit that matches the description: 1. a mass that is 1000 times greater than 1 gram 1) kilogram 2) milligram 3) megagram 2. a length that is 1/100 of 1 meter 1) decimeter 2) centimeter 3) millimeter 3. a unit of time that is 1/1000 of a second 1) nanosecond 2) microsecond 3) millisecond = 0.01 of 1 meter = 0.001 of a sec

Learning Check Select the unit you would use to measure A. your height 1) millimeters 2) meters 3) kilometers B. your mass 1) milligrams 2) grams 3) kilograms C. the distance between two cities D. the width of an artery

Solution Select the unit you would use to measure A. your height 1) millimeters 2) meters 3) kilometers B. your mass 1) milligrams 2) grams 3) kilograms C. the distance between two cities D. the width of an artery

Metric Equalities States the same measurement in two different units Length: 1 meter is the same as 100 cm or 1000 mm. 1 m = 100 cm 1 m = 1000 mm Volume: 1 L is the same as 1000 cm3. 1 L = 10 cm X 10cm X 10 cm 1 L = 1000 mL Mass: 1 kg = 1000 g 1 g = 1000 mg 1 mg = 0.001 g 1 mg = 1000 µg

Learning Check Indicate the unit that completes each of the following equalities: A. 1000 m = 1) 1 mm 2) 1 km 3) 1dm B. 0.001 g = 1) 1 mg 2) 1 kg 3) 1dg C. 0.1 s = 1) 1 ms 2) 1 cs 3) 1ds D. 0.01 m = 1) 1 mm 2) 1 cm 3) 1dm

Solution Indicate the unit that completes each of the following equalities: A. 1000 m = 1) 1 mm 2) 1 km 3) 1dm B. 0.001 g = 1) 1 mg 2) 1 kg 3) 1dg C. 0.1 s = 1) 1 ms 2) 1 cs 3) 1ds D. 0.01 m = 1) 1 mm 2) 1 cm 3) 1dm

Learning Check Complete each of the following equalities: A. 1 kg = 1) 10 g 2) 100 g 3) 1000 g B. 1 mm = 1) 0.001 m 2) 0.01 m 3) 0.1 m

Solution Complete each of the following equalities: A. 1 kg = 1) 10 g 2) 100 g 3) 1000 g B. 1 mm = 1) 0.001 m 2) 0.01 m 3) 0.1 m

Writing Conversion Factors Chapter 1 Measurements 1.6 Writing Conversion Factors

Measurements in chemistry See Handout Sheet of Common conversion factors & Handout of Conversion Problems

Some Common Equalities

Learning Check Write equalities and conversion factors for each pair of units: A. liters and mL B. hours and minutes C. meters and kilometers

Solution Write equalities and conversion factors for each pair of units: A. liters and mL B. hours and minutes C. meters and kilometers Equality: 1 L = 1000 mL 1 L and 1000 mL 1000 mL 1 L Equality: 1 hr = 60 min 1 hr and 60 min 60 min 1 hr Equality: 1 km = 1000 m 1 km and 1000 m 1000 m 1 km

Learning Check Write the equality and conversion factors for each of the following: A. meters and centimeters B. jewelry that contains 18% gold C. one liter of gas is $ 0.95

Solution A. meters and centimeters 1 m and 100 cm 100 cm 1 m B. jewelry that contains 18% gold 18 g gold and 100 g jewelry 100 g jewelry 18 g gold C. one liter of gas is $0.95 1 L and $0.95 $0.95 1 L

Chapter 1 Measurements 1.7 Problem Solving

Conversion of units Example: Metric Conversion 1 kg = 1 1000 g How many milligrams (mg) are in 5 kilograms (kg)? Factor label method Identify your conversions factors. 1 kg = 1 1000 g 1000 mg = 1 1 g 1000 g = 1 1 kg 1 g = 1 1000 mg

unique Example: Metric Conversion 5 kg = mg How many milligrams are in 5 kilograms? Identify what is to the problem. unique 5 kg = mg Identify how you want the answer to look.

Example: Metric Conversion How many milligrams are in 5 kilograms? Multiply by conversion factors until units cancel. 5 kg 1 1000 g 1 kg 1000 mg 1 g = mg 5,000,000 If the words work, the numbers will work.

Example: Metric Conversion How many decimeters are there in 5.5 meters? How many meters are there in 25 centimeters?

Practice : Metric Conversion How many meters are in 3 kilometers? 3000 m = 3 km How many milliliters are in 0.5 liters? 500 mL = 0.5 L How many grams are in 2.5 kg? 2500 g = 2.5 kg How many millimeters are in 1 meter? 1000 mm = 1 m

Example: English Conversion How many teaspoons in a barrel of oil? 1 barrel of oil = 42. gallons 1 gallon = 4 quarts 1 quart = 4 cups 1 cup = 16 tablespoons 1 tablespoon = 3 teaspoons 32,256 1 bal 42 gal 1 bal 4 qt 1 gal 4 cup 1 qt 16 Tbl 1 cup 3 tsp 1 Tbl = tsp 32,000 tsp

Practice: English-Metric Conversion 454 g = 1 lb 1 L = 1.06 qt 2.54 cm = 1 in How many grams are there in 125 pounds? How many inches are there in 8.7 meters?

Example: English-Metric Conversion You have a pen of rats each with an average weight of 0.75 lb. How much rubbing alcohol will it take to kill ½ of the population if the LD50 is 5000. mg/kg ? Identify your conversions factors. 1 kg Bw = 1 5000 mg Alc 1.0 kg Bw = 1 2.2 lb Bw 5000 mg Alc = 1 1 kg Bw 2.2 lb Bw = 1 1.0 kg Bw

Example: English-Metric Conversion You have a pen of rats each with an average weight of 0.75 lb. How much rubbing alcohol will it take to kill ½ of the population if the LD50 is 5000. mg/kg ? Identify what is unique to the problem. 1.0 kgBW 2.2 lbBW 5000. mgAlc 1 kg BW 0.75 lbBW = mgAlc 1704.545 1700 mg = 1.7 x 103 Identify how you want the answer to look.

Example: How many minutes are 2.5 h? Given (unique) = 2.5 h Needed unit = ? min Plan = h  min Set up problem to cancel hours (h). Given Conversion Needed unit factor unit 2.5 h x 60 min = 150 min (2 SigFigs) 1 h

Learning Check A rattlesnake is 2.44 m long. How many centimeters long is the snake? 1) 2440 cm 2) 244 cm 3) 24.4 cm

Solution Given (Unique) unit: 2.44 m Needed unit: cm Plan: m  cm Equality: 1 m = 100 cm Factors: 1 m and 100 cm 100 cm 1 m Set up problem: 2.44 m x 100 cm = 244 cm (answer 2) 1 m

Example: How many minutes are 1.6 days? Given (unique) = 1.6 days Needed unit = ? min Plan = days  hours  min Set up problem to cancel hours (h). 1.6 days x 24 hrs x 60 min = 1 day 1 hr 2300 min = 2.3 x 103 2 SigFigs Exact Exact = 2 SigFigs

Check the Unit Cancellation Be sure to check your unit cancellation in the setup. The units in the conversion factors must cancel to give the correct unit for the answer. Example: What is wrong with the following setup? 1.4 day x 1 day x 1 h 24 h 60 min Units = day2/min, which is not the unit needed Units don’t cancel properly. Therefore, setup is wrong.

Learning Check A bucket contains 4.65 L of water. How many gallons of water is that? Given: 4.65 L Need: gal Plan: L  qt  gal Equalities: 1.06 qt = 1 L 1 gal = 4 qt

Solution Given : 4.65 L Need: gal Plan: L  qt  gallon Equalities: 1.06 qt = 1 L; 1 gal = 4 qt Set up problem: 4.65 L x 1.06 qt x 1 gal = 1.23 gal 1 L 4 qt 3 SF 3 SF exact 3 SF

Learning Check If a ski pole is 3.0 feet in length, how long is the ski pole in mm?

Solution Given: 3.0 ft Need: mm Plan: ft  in.  cm  mm Equalities: 1 ft = 12 in. 2.54 cm = 1 in. 1 cm = 10 mm Set up problem: 3.0 ft x 12 in. x 2.54 cm x 10 mm = 910 mm 1 ft 1 in. 1 cm Check initial unit: ft Check needed unit: mm Check factor setup: units cancel properly (2SigFigs, rounded)

Learning Check If your pace on a treadmill is 65 meters per minute, how many minutes will it take for you to walk a distance of 7500 feet?

Solution Given: 7500 ft, 65 m/min Need: min Plan: ft in. cm m min Equalities: 1 ft = 12 in. 1 in. = 2.54 cm 1 m = 100 cm 1 min = 65 m (walking pace) Set up problem: 7500 ft x 12 in. x 2.54 cm x 1m x 1 min 1 ft 1 in. 100 cm 65 m = 35 min (2SF)

Learning Check How many pounds (lb) of sugar are in 120 g of candy if the candy is 25% (by mass) sugar?

Solution How many pounds (lb) of sugar are in 120 g of candy if the candy is 25% (by mass) sugar? percent factor 120 g candy x 1 lb candy x 25 lb sugar 454 g candy 100 lb candy = 0.066 lb of sugar

Percentages Part x 100 = % Whole ___ 100 13 males x 100 = 37.1429 % Secret code for 13 males x 100 = 37.1429 % 35 Students 37% male

Percentages as Conversion Factors Example: The population of the automotive repair course is 37% male. Of the 75 students in the class how many are men? 37 male 100 students 37% male = Secret code for 100 students 37 male

Percentages as Conversion Factors Example: The population of the automotive repair course is 37% male. Of the 75 students in the class how many are men? Identify what is to the problem. unique 75 students 1 37 males 100 students = males 27.75 28 males Identify how you want the answer to look.

Percentages Part x 100 = Whole % ___ 100 10 % Alcohol = 100 mL Secret code for 10 % Alcohol = 100 mL 10 mL Alcohol Solution

Percentages as Conversion Factors Example: An athlete normally has 15 % body fat. How many lbs of fat does a 74 kg athlete have? 15 lb Fat 100 lb BW 15% Body Fat = Secret code for 100 lb BW 15 lb Fat

Percentages as Conversion Factors Example: An athlete normally has 15 % body fat. How many lbs of fat does a 74 kg athlete have? Identify what is to the problem. unique 15 lb Fat 100 lb BW 74 KgBw 2.2 lbBw 1.0 KbBw = lb fat 24.42 24 lb fat Identify how you want the answer to look.

Learning Check: If the thickness of the skin fold at the waist indicates an 11% body fat, how much fat is in a person with a mass of 86 kg?

Solution: If the thickness of the skin fold at the waist indicates an 11% body fat, how much fat is in a person with a mass of 86 kg? 11% body fat means 11 kg fat 100 kg 86 kg x 11 kg fat = 9.5 kg of fat

Chapter 1 Measurements 1.8 Density

Density Density = At 4 o C Mass Volume g Water 1.0 Urine 1.01 - 1.03 1cc = 1 cm3 = 1 ml = 1 g water g cm3 g ml At 4 o C or Water 1.0 Urine 1.01 - 1.03 Air 0.0013 Bone 1.7 - 2.0 Gold 19.3 Gasoline 0.66 - 0.69

Densities of Common Substances

Example. Density calculation What is the density of 5.00 ml of serum if it has a mass of 5.230 grams? d = m V d = 5.230 g 5.00 ml = 1.05 g ml

Guide to Calculating Density d = m V

Learning Check Osmium is a very dense metal. What is its density in g/cm3 if 50.0 g of osmium has a volume of 2.22 cm3? 1) 2.25 g/cm3 2) 22.5 g/cm3 3) 111 g/cm3

Solution Given: mass = 50.0 g ,volume = 22.2 cm3 Need: Density Plan: Place the mass and volume of the osmium metal in the density expression. D = mass = 50.0 g volume 2.22 cm3 Calculator = 22.522522 g/cm3 Final answer (2 SF) = 22.5 g/cm3

Practice: Density The mass of a 6.85 mL sample of a liquid is found to weigh 7.453 grams. What is the density of the liquid? The specific gravity equals 1.09 and as a ratio, has no units.

Practice: Density The mass of a 4.96 cm3 sample of gold is found to weigh 95.78 grams. What is the density of the liquid? (1.00mL = 1.00cm3)

Volume by Displacement A solid completely submerged in water displaces its own volume of water. The volume of the solid is calculated from the volume difference. 45.0 mL – 35.5 mL = 9.5 mL = 9.5 cm3

Density Using Volume Displacement The density of the zinc object is calculated from its mass and volume. mass = 68.60 g = 7.2 g/cm3 volume 9.5 cm3

Learning Check What is the density (g/cm3) of 48.0 g of a metal if the level of water in a graduated cylinder rises from 25.0 mL to 33.0 mL after the metal is added? 1) 0.17 g/cm3 2) 6.0 g/cm3 3) 380 g/cm3 33.0 mL 25.0 mL object

Solution Given: 48.0 g Volume of water = 25.0 mL Volume of water + metal = 33.0 mL Need: Density (g/cm3 ) Plan: Calculate the volume difference. Change to cm3, and place in density expression. 33.0 mL – 25.0 mL = 8.0 mL 8.0 mL x 1 cm3 = 8.0 cm3 1 mL Set up problem: Density = 48.0 g = 6.0 g = 6.0 g/cm3 8.0 cm3 1 cm3 (2 SF)

Sink or Float Ice floats in water because the density of ice is less than the density of water. Aluminum sinks in water because its density is greater than the density of water.

Learning Check K W V V W K W V K Which diagram correctly represents the liquid layers in the cylinder? Karo (K) syrup (1.4 g/mL), vegetable (V) oil (0.91 g/mL), water (W) (1.0 g/mL) 1 2 3 K W V V W K V W K

Solution V W K vegetable oil (0.91 g/mL) water (1.0 g/mL) 1) vegetable oil (0.91 g/mL) water (1.0 g/mL) Karo syrup (1.4 g/mL) V W K

Density as a Conversion A liquid sample with a density of 1.09 g/mL is found to weigh 7.453 grams. What is the volume of the liquid in mLs? Identify any conversion factors. What is unique to the problem? 7.453 g 1 ml 1.09 g = ml 6.837614 = 6.84 ml How should the answer look? 1.09 g 1 ml 1 ml 1.09 g

Learning Check The density of octane, a component of gasoline, is 0.702 g/mL. What is the mass, in kg, of 875 mL of octane? 1) 0.614 kg 2) 614 kg 3) 1.25 kg

Solution The density of octane, a component of gasoline, is 0.702 g/mL. What is the mass, in kg, of 875 mL of octane? 1) 0.614 kg 2) 614 kg 3) 1.25 kg Given: D = 0.702 g/mL V = 875 mL Need: kg Plan: mL  g  kg Equalities: density 0.702 g = 1 mL and 1 kg = 1000 g Set up problem: 875 mL x 0.702 g x 1 kg = 0.614 kg 1 mL 1000 g

Learning Check If olive oil has a density of 0.92 g/mL, how many liters of olive oil are in 285 g of olive oil? 1) 0.26 L 2) 0.31 L 3) 310 L

Solution If olive oil has a density of 0.92 g/mL, how many liters of olive oil are in 285 g of olive oil? 1) 0.26 L 2) 0.31 L 3) 310 L Given: D = 0.92 g/mL mass = 285 g Need: volume in L Plan: g  mL  L Equalities: 1 mL = 0.92 g 1 L = 1000 mL Set up: 285 g x 1 mL x 1 L = 0.31 L 0.92 g 1000 mL density metric factor factor

Learning Check A group of students collected 125 empty aluminum cans to take to the recycling center. If 21 cans contain 1.0 lb of aluminum, how many liters of aluminum (D = 2.70 g/cm3) are obtained from the cans? 1) 1.0 L 2) 2.0 L 3) 4.0 L

Solution A group of students collected 125 empty aluminum cans to take to the recycling center. If 21 cans contain 1.0 lb of aluminum, how many liters of aluminum (D = 2.70 g/cm3) are obtained from the cans? 1) 1.0 L 2) 2.0 L 3) 4.0 L 125 cans x 1.0 lb x 454 g x 1 cm3 x 1 mL x 1 L 21 cans 1 lb 2.70 g 1 cm3 1000 mL = 1.0 L

Learning Check Which of the following samples of metals will displace the greatest volume of water? 1 2 3 25 g of aluminum 2.70 g/mL 45 g of gold 19.3 g/mL 75 g of lead 11.3 g/mL

Solution 25 g of aluminum 2.70 g/mL 1) Plan: Calculate the volume for each metal, and select the metal sample with the greatest volume. 1) 25g x 1 mL = 9.3 mL of aluminum 2.70 g 2) 45 g x 1 mL = 2.3 mL of gold 19.3 g 3) 75 g x 1 mL = 6.6 mL of lead 11.3 g

density = specific gravity (if at 4oC) density of substance g ml Specific Gravity = density of reference g ml Reference commonly water at 4oC density = specific gravity (if at 4oC) Specific Gravity is unitless.

Commonly used to test sugar in urine. based on Specific Gravity. Hydrometer Commonly used to test sugar in urine. Float height will be based on Specific Gravity.