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0: Math and Measurement

Learn the math and measurement skills needed to excel in chemistry. Topics include lab safety, scientific notation, and significant figures.

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0: Math and Measurement

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  1. 0: Math and Measurement What math and measurement skills will I need to be successful in chemistry?

  2. Grab all materials from by the door. • Locate your assigned seat. Drill:9/4 (A Day)9/5 (B Day) Outcome: I can identify lab equipment and write numbers in scientific notation Goal: CW 1, CW 2, CW 3

  3. CW 1: Safety in the Chemistry Lab • Who has responsibilities for safety? • The student and the teacher. • What types of clothing are appropriate to wear during a lab? • Goggles, closed toe shoes, no baggy/ loose clothes, no dangling jewelry, tie back hair. • What should you do with backpacks and extra personal belongings during lab? • Put away unnecessary items in backpacks under your desk. Keep walkways clear. • What do you never ever do in a science laboratory? • Eat or drink anything.

  4. CW 1: Safety in the Chemistry Lab • What are the two types of safety equipment? Give an example of each. • Classroom: Eye wash, fire blanket, fire extinguisher, first aid, safety shower. • Personal: Goggles, gloves, apron. • What does this acronym stand for when using a fire extinguisher? • P: Pull the pin • A: Aim at the base of the flame • S: Squeeze the handle • S: Sweep back and forth

  5. CW 1: Safety in the Chemistry Lab • What is the correct way to smell a substance? • Gently waft. • How should you transport chemicals across a classroom? • Walk defensively, elbows in, use both hands. • How should you clean up broken glass? • Use a dustpan and broom. Only pick up glass with safety gloves.

  6. CW 1: Safety in the Chemistry Lab • Where are the following located? • Door • Eyewash station • Safety shower • Fire extinguisher • Fire blanket • First aid kit • Waste beakers

  7. CW 1: Safety in the Chemistry Lab • What should you do if you are unsure of how to proceed during an experiment? • Ask for help. • Why should you not immerse hot glassware into cold water? • It can shatter. • Where should you dispose of chemical wastes? • As directed by your teacher. Do not return unused chemicals to their containers. Do not pour substances down the drain without checking with your teacher. • Where should you point a mouth of a test tube that is being heated? • Away from yourself and others.

  8. CW 2: Lab Equipment • Introduce yourself to your group members: • First and Last Name • Answer your question # • On your lab bench, you will find a box of laboratory equipment. Go through the box, highlighting each item that you find. • You will have a short quiz on these items next class. • Quiz each other! • 5 minutes total!

  9. CW 3: Scientific Notation • In order to write a number in scientific notation: • Move the decimal so that there is only ONE number before it. • Count how many spaces you moved the decimal. This is the exponent. A big number has a positive exponent and a small number has a negative exponent. • Write out the decimal, then write “x10”, then write the exponent as a superscript.

  10. CW 3: Scientific Notation • Write each of the following in scientific notation • 0.000033 • 465 • 236,000,000,000 • 0.000000000000236 • Write each of the following in decimal notation. • 3.7 x 105 • 3.21 x 10-4 • 1.99 x 10-3 • 1.7 x 1012 • 8.653 x 10-17 = 3.3x10-5 = 4.65x102 = 2.36x1011 = 2.36x10-13 = 370,000 = 0.000321 = 0.00199 = 1,700,000,000,000 = 0.00000000000000008653

  11. CW 3: Scientific Notation • When you want to add three zeros to a number, such as going from 1,000 to 1,000,000, how many additional powers of 10 are required? • What makes a billionth different from a billion or a hundredth different from a hundred? How does this relate to the plus or minus sign written with the exponent? 1,000 1,000,000 3 additional powers of 10 Sign indicates if it’s a big number or a small number. Hundredth: Hundred:

  12. CW 3: Scientific Notation • When you write out 102 or 103, do you write the zeros before or after the 1? • Positive exponent = big number, zeros after 1 • When you write out 10-2 or 10-3, do you write the zeros before or after the 1? • Negative exponent = small number, zeros before 1

  13. Complete CW 1 and CW 2 if not complete • HW 1: Scavenger Hunt • Signatures (syllabus, safety contract) • Locate googles • Complete Page 1 from SciResearch, due 9/11 (A Day) and 9/12 (B Day) Summary:9/4 (A Day)9/5 (B Day) Outcome: I can identify lab equipment and write numbers in scientific notation Goal: CW 1, CW 2, CW 3

  14. Read the significant figures fable then answer the questions below. • Is asking for a cube with a 2.1 cm edge the same thing as asking for a cube with a 2.097 cm edge? Explain. • No! 2.097 cm is much more precise then 2.1 cm. • Why was there a difference in price and time? • The cube needed to be grinded and lapped down to THREE DECIMAL PLACES! • One cube was too small • Required special (expensive) equipment Drill 1:9/6 (A Day)9/9 (B Day) Outcome: I can express measured numbers with correct significant figures Goal: Quiz, CW 4, CW 5 Hand In: signed syllabus, signed safety contract, put googles in google bin

  15. HW 1: Scavenger Hunt • Volumetric flask • 3: Holey Moley • Safety Contract 2018-2019 • Test Reviews • “For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.” -Carl Sagan, The Demon-Haunted World • CC-BY-NC-SA 4.0

  16. Lab Equipment Quiz • Any questions? • Number a sheet of loose leaf 1 to 5 and put your name on it. • Clear off desks except for a writing utensil. • Copying/ Cheating = zero. Don’t try.

  17. CW 4: Scientific Measurement • Provide a definition for accuracy: • How close your measurements are to the correct value • Provide a definition for precision: • How close each measurement is to each other Instrument may need to be calibrated Change your experiment to get better results.

  18. CW 4: Scientific Measurement • A chemistry student finds a piece of gum to contain 3.2 grams of sugar. According to the nutrition facts, the gum has 4.0 grams of sugar. There iserrorassociatedwithanymeasurement!

  19. CW 4: Scientific Measurement Ruler goes from 0 to 1; I have to guess the first decimal place. I can’t guess a second decimal place because I wasn’t even sure about the first. 0.7 m This ruler has more tick marks. Now I am sure of the first decimal (I can read it off of the ruler), so I have to guess the second. 0.78 m 0.771 m More tick marks; now I’m sure about the first and second decimal because I can read it off the ruler; I have to guess the third decimal place.

  20. CW 4: Scientific Measurement • What is different about each of the rulers? • The number of tick marks. • Explain why the bottom ruler can measure out to more decimal places than the top ruler. • The tick marks allow us to measure to smaller places – we always guess one place smaller than the tick marks provide. • Which ruler do you think allows the most precision? Explain. • The bottom ruler which has the most tick marks.

  21. CW 4: Scientific Measurement • Measure each of the following graduated cylinders. UNITS! How can there be more than one right answer? There is error associated with any measurement! Error could be human or instrumental (from the instrument you are using to measure).

  22. CW 4: Scientific Measurement • Measure each of the following, writing your answer with units. 69.55 cm 69.54 cm 69.56 cm 61.955 cm 61.954 cm 61.956 cm 41.19 cm 41.20 cm 41.18 cm

  23. CW 4: Scientific Measurement • Measure each of the following, writing your answer with units. 7.8 cm 7.7 cm 7.6 cm 0.78 cm 0.77 cm 0.76 cm 78 cm 77 cm 76 cm

  24. CW 5: Significant Figures Basics RULES TO DETERMINE THE NUMBER OF SIG FIGS • All digits 1 to 9 are significant. • 335 • 5.684 • All digits used in scientific notation are considered significant. • 3.25x10-5 • 5.00x103 • “Sandwiched” zeroes are significant. • 4005 • 1.4057

  25. CW 5: Significant Figures Basics RULES TO DETERMINE THE NUMBER OF SIG FIGS • When dealing with other zeros, ask yourself: Is there a decimal? Does the zero come after a number? If the answer to both is yes, then the zero is significant. • 56.00 • 9.00 • 4.060 • 0.00071 • 0.35 • 300 • 125,000 • 300. • 125,000.

  26. CW 5: Significant Figures Basics RULES TO DETERMINE THE NUMBER OF SIG FIGS • Constants and counted numbers have unlimited significant figures. • 28 students in chemistry class today • Speed of light in a vacuum: 3.0x108

  27. CW 5: Significant Figures Basics • Determine the number of significant figures in each of the following. 1, 4 1, 4 1 2 1, 3, 4 1, 3 4 3 1, 4 1, 4 4 1 6 2 1, 3, 4 3 3 1, 3, 4 5 4

  28. CW 5: Significant Figures Basics • Once you feel confident with the examples give above, take the learning check quiz below. • You can go to the link or scan the QR code with your phone. • This is NOT a grade, just a way to check your understanding. • When you finish, click on the “View your score” link. Use the feedback to reflect on your answers. List any you got wrong, along with the correct answer below. http://goo.gl/forms/600eHK9YcArSwcH23

  29. Complete CW 4 and CW 5 • HW 2: Sig Figs Practice I • Complete Page 1 from SciResearch, due 9/11 (A Day) and 9/12 (B Day) Summary 1:9/6 (A Day)9/9 (B Day) Outcome: I can express measured numbers with correct significant figures Goal: Quiz, CW 4, CW 5 Hand In: signed syllabus, signed safety contract, put googles in google bin

  30. How many sig figs are in the following? • 0.0160 cm • 32 balloons • 5.6000x1024 kg • 500 miles • And 500. more miles Drill 2:9/10 (A Day)9/11 (B Day) Outcome: I can give correct sig figs in multi step math problems Goal: CW 6 Hand In: 1 Benefits of doing a Science Research Project Reflection

  31. HW 2: Sig Figs Practice I • Sig Figs Table: • D • Counted numbers, constants • Rounding: • 65.15m • 100 °C • 160 cm • 0.00072 kg • 65.1 m

  32. CW 6: Using Significant Figures • The top code will take you to an instructional video; answer keys are up front with Ms. L • Each page has two sets of problems: • Top set: required • Bottom set: optional, if you feel you need more practice • Work in groups; if you cannot figure something out in your group, raise your hand.

  33. CW 6: Using Significant Figures • When adding or subtracting, we round to the least precise place.

  34. CW 6: Using Significant Figures • When multiplying or dividing, we round to the fewest number of sig figs.

  35. CW 6: Using Significant Figures • In multistep problems, we save rounding for the end.

  36. Complete CW 6 • HW 3: Sig Figs Practice II • Complete Page 2 from SciResearch due, 9/17 (A Day) and 9/18 (B Day) Summary 2:9/10 (A Day)9/11 (B Day) Outcome: I can give correct sig figs in multi step math problems Goal: CW 6 Hand In: 1 Benefits of doing a science research project reflection

  37. 2.5 cm + 0.50 cm + 0.055 cm = • 3.055 cm • 3.06 cm • 3.1 cm • 3 cm • 0.530 g / 0.1010 mL = Drill 3:9/12 (A Day)9/13 (B Day) Outcome: I can convert between metric unit using dimensional analysis. Goal: CW 7, CW 8

  38. HW 3: Sig Figs Practice II • 5 cm • 10,000 m • 7 mol • 7.80x103 mm • 79.2 g • 81.50 s • 8900 mg • 2.6 K • 30.5 g • 3.9 Mmol

  39. Significant Figures Quiz • Complete the quiz, no phones as calculators. • If you finish early, start working individually on CW 7.

  40. CW 7: Metric Prefixes • What do these have in common: US, Liberia, Myanmar?

  41. *Note: There are more prefixes, these are just the ones we use the most. CW 7: Metric Prefixes

  42. CW 7: Metric Prefixes • For each of the following, write the correct abbreviation. • Millimeter = • Kilogram = • Centisecond = • Millimole = • Nanometer = • Kelvin = mm kg cs mmol nm K

  43. CW 7: Metric Prefixes • For each of the following, determine the correct conversion factor • How many meters are in a kilometer? • How many milliliters are in a liter? • How many grams are in a kilogram? • How many kilograms are in a gram? 1 m = 1000 km 1000 m = 1 km 1000 mL = 1 L 1 mL = 1000 L 1 g = 1000 kg 1000 g = 1 kg 0.001 g = 1 kg 1 g = 0.001 kg

  44. CW 8: Dimensional Analysis • Cancel out the units and solve. • How many seconds are in 2.3 years? • Now solve. min    2.3 years sec  days hours

  45. CW 8: Dimensional Analysis • Convert 1.23 L into mL. • Convert 56.0 mm into cm. 1000 mL = 1 L

  46. CW 8: Dimensional Analysis • How many miles are in 200 cm? Write your answer in scientific notation. (1 mile = 5280 ft, 1 ft = 12 inches, 1 inch = 2.54 cm)

  47. CW 8: Dimensional Analysis • You are travelling in the car at 50 miles per hour. How many feet per second is this? (1 mile = 5280 feet)

  48. Dimensional Analysis Pretest • Answer on the scantron sheet • 10 minutes, just do the ones you can

  49. Index Card Assessment • Obtain an index card from your teacher. • Label your card to look like the picture below. Write neatly. • Using your assigned ruler, determine the length (long side) and width (short side) of the index card in cm, measured to the correct precision (decimal place). • On the unlined (back) side of the card, show the dimensional analysis to convert the length and width from cm into mm. • Write the length and width in both cm and mm on the lined side of the card. • On the lined side of the card, using your measured values in mm, determine the perimeter and the area of the card. • Show the calculation for area and perimeter on the unlined (back) of the card. • Give the unrounded answer, the answer with correct sig figs, and the answer with correct sig figs in scientific notation. • Don’t forget to include a unit after each number!

  50. Complete CW 7 and CW 8 • HW 4: Dimensional Analysis Practice • Index Card Assessment due, 9/20 (A Day) and 9/21 (B Day) • Complete Page 2 from SciResearch due, 9/17 (A Day) and 9/18 (B Day) Summary 3:9/12 (A Day)9/13 (B Day) Outcome: I can convert between metric unit using dimensional analysis. Goal: CW 7, CW 8

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