Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Opener #7 - WED - AUGUST 29, 2012 Pick up calculator. Have out Notes ch. 2 packet. 1. What are the base SI units for time, length, mass, and temperature? 2. How many grams are in 45 kilograms? 3. How many quarters are in $50? 4. What is the volume of an unknown sample that has a density of 0.5 g/mL and a mass of 2.0 grams. CW: Class Notes 2.2C-2.3 Using Dimensional Analysis for Conversions, Accuracy vs. Precision, % Error, AND Significant Figures. HW: Study Guide Questions are due Friday TEST Unit 1 (ch.1-2) is WED. Sept. 5th. STUDY!!!! Turned in the 2 lab sheets yesterday if absent..

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Opener #8 - THURS - JAN. 17, 2013 Pick up calculator. Have out Notes ch. 2 packet. Pick up opener #8 half-sheet handout for Significant figures and get out your notes packet to be ready to start. CW: Class Notes 2.2C-2.3 Using Dimensional Analysis for Conversions CW: Dimensional Analysis worksheet - use T-chart method and turn in with lab sheet on other side when done. HW: Study Guide Questions due tomorrow but will not be counted as grade until next week. Come with questions and have all of the questions answered that you can. TEST Unit 1 (ch.1-2) is WED. JAN. 23rd - STUDY!!!! Turned in the first lab sheets yesterday if absent.. MAKE UP for 2 LABs today after class ONLY TODAY!

End Show © Copyright Pearson Prentice Hall 3 Slide of C Conversion Problems using Dimensional Analysis Because each country’s currency compares differently with the U.S. dollar, knowing how to convert currency units correctly is very important. Conversion problems are readily solved by a problem- solving approach called dimensional analysis.

End Show © Copyright Pearson Prentice Hall 4 Conversion Problems > Slide of 43 Conversion Factors What happens when a measurement is multiplied by a conversion factor? 2.2C

End Show © Copyright Pearson Prentice Hall 5 Slide of 43 Conversion Problems > 2.2C Conversion Factors A conversion factor is a ratio of equivalent measurements. The ratios 100 cm/1 m and 1 m/100 cm are examples of conversion factors. They are equal to 1.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Conversion Factors A conversion factor is a ratio derived from the equality between two different units that can be used to convert from one unit to the other. Section 2 Units of Measurement Chapter 2 example: How quarters and dollars are related

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Conversion Factor Chapter 2 dent/ch02/sec02/vc03/hc602_02_v03fs.htm

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Conversion Factors, continued Dimensional analysis is a mathematical technique that allows you to use units to solve problems involving measurements. Section 2 Units of Measurement Chapter 2 example: the number of quarters in 12 dollars number of quarters = 12 dollars  conversion factor quantity sought = quantity given  conversion factor

End Show © Copyright Pearson Prentice Hall 9 Slide of 43 Conversion Problems > 2.2 Conversion Factors When a measurement is multiplied by a conversion factor, the numerical value is generally changed, but the actual size of the quantity measured remains the same.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu METRIC CONVERSION PROBLEM ACTIVITY CLICK HERE TO SEE CONVERSION FACTOR PROBLEM ACTIVITY I will make up own problem if teacher leading notes such as how many seconds have you been alive after doing a few easier examples.

I II III C. Johannesson III. Unit Conversions (Modern Chemistry Holt p ) CH. 2 - MEASUREMENT

= A. SI Prefix Conversions NUMBER UNIT NUMBER UNIT 532 m = _______ km 0.532

B. Dimensional Analysis  The “Factor-Label” Method (also called Dimensional Analysis)  Units, or “labels” are canceled, or “factored” out

B. Dimensional Analysis  Steps:  1. Identify starting & ending units.  2. Line up conversion factors so units cancel.  3. Multiply all top numbers & divide by each bottom number.  4. Check units & answer.

B. Dimensional Analysis  Lining up conversion factors: 1 in = 2.54 cm 2.54 cm 1 in = 2.54 cm 1 in 1 in = 11 =

B. Dimensional Analysis  Convert 4432 mm to km mm 1 m 1000 mm = km mmkm 1 km 1000 m 

B. Dimensional Analysis  Study this before trying the next problems. How many milliliters are in 1.00 quart of milk? Reference shows qts = 1 L 1.00 qt 1 L qt = 946 mL qtmL 1000 mL 1 L 

B. Dimensional Analysis  #1) You have 1.5 pounds of gold. Find its volume in cm 3 if the density of gold is 19.3 g/cm 3. (2.2 pounds = 1 kg) lbcm lb 1 kg 2.2 lb = 35 cm g 1 kg 1 cm g

B. Dimensional Analysis  #2) How many liters of water would fill a container that measures 75.0 in 3 ? 75.0 in 3 (2.54 cm) 3 (1 in) 3 = 1.23 L in 3 L 1 L 1000 cm 3

B. Dimensional Analysis  #3) Your European hairdresser wants to cut your hair 8.0 cm shorter. How many inches will he be cutting off? 8.0 cm1 in 2.54 cm = 3.1 in cmin

B. Dimensional Analysis  #4) Taft football needs 550 cm for a 1st down. How many yards is this? 550 cm 1 in 2.54 cm = 6.0 yd cmyd 1 ft 12 in 1 yd 3 ft

B. Dimensional Analysis  #5) A piece of wire is 1.3 m long. How many 1.5-cm pieces can be cut from this wire? 1.3 m 100 cm 1 m = 86 pieces mpieces 1 piece 1.5 cm

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu - THURS - JAN. 17, 2013 ASSIGNMENTS CW: Dimensional Analysis worksheet - use T-chart method and turn in with lab sheet on other side when done. HW: Study Guide Questions due tomorrow but will not be counted as grade until next week. Come with questions and have all of the questions answered that you can. TEST Unit 1 (ch.1-2) is WED. JAN. 23rd - STUDY!!!! Turned in the first lab sheets yesterday if absent.. MAKE UP for 2 LABs today after class ONLY TODAY! Catch up on Notes if you have been absent after doing the Dimensional Analysis sheet.

End Show © Copyright Pearson Prentice Hall 24 Measurements and Their Uncertainty > Slide of 48 Accuracy, Precision, and Error How do you evaluate accuracy and precision? 2.3

End Show © Copyright Pearson Prentice Hall 25 Measurements and Their Uncertainty > Slide of Accuracy, Precision, and Error Accuracy and Precision Accuracy is a measure of how close a measurement comes to the actual or true value of whatever is measured. Precision is a measure of how close a series of measurements are to one another.

End Show © Copyright Pearson Prentice Hall 26 Measurements and Their Uncertainty > Slide of Accuracy, Precision, and Error To evaluate the accuracy of a measurement, the measured value must be compared to the correct value. To evaluate the precision of a measurement, you must compare the values of two or more repeated measurements.

End Show © Copyright Pearson Prentice Hall 27 Measurements and Their Uncertainty > Slide of Accuracy, Precision, and Error

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Accuracy and Precision Section 3 Using Scientific Measurements Chapter 2

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Accuracy and Precision Chapter 2 udent/ch02/sec03/vc00/hc602_03_v00fs.h tm

End Show © Copyright Pearson Prentice Hall 30 Measurements and Their Uncertainty > Slide of Accuracy, Precision, and Error Just because a measuring device works, you cannot assume it is accurate. The scale below has not been properly zeroed, so the reading obtained for the person’s weight is inaccurate.

End Show © Copyright Pearson Prentice Hall 31 Measurements and Their Uncertainty > Slide of Accuracy, Precision, and Error Determining Error The accepted value is the correct value based on reliable references. The experimental value is the value measured in the lab. The difference between the experimental value and the accepted value is called the error.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Accuracy and Precision, continued Percentage Error Percentage error is calculated by subtracting the accepted value from the experimental value, dividing the difference by the accepted value, and then multiplying by 100. Section 3 Using Scientific Measurements Chapter 2

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Percentage Error Visual Concept Click below for Visual Concept Section 3 Using Scientific Measurements Chapter 2 Click for Visual Concept on Percent Error

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu PERCENT ERROR PROBLEM ACTIVITY CLICK HERE FOR PERCENT ERROR PROBLEM ACTIVITY

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Opener #8 - THURSDAY - AUGUST 30, Using Dimensional Analysis, show the age of a 16 year old student whose birthday is today at this exact moment in the number of seconds the student has been alive. 2. Describe the difference between precision and accuracy in your own words. 3. Convert 5.4 feet to millimeters showing all work with Dimensional Analysis. (2.54 cm = 1 inch) CW: Notes Significant Figures CW: Bingo Game CW: If time, metric puzzle game HW: Study Guide questions due tomorrow; TEST 9/5 WED HW/CW: Pre-lab side of w/sheet - due tomorrow - other side dueTuesday

B. Dimensional Analysis  #1)Show the age of a 16 year old student whose birthday is today at this exact moment in the number of seconds the student has been alive. yearsseconds 16 yrs days 1 yr = 504,921,600 s 24 hrs 1 day 60 min 1 hr 60 sec 1 min

B. Dimensional Analysis  3. Convert 5.4 feet to millimeters showing all work with Dimensional Analysis. – (2.54 cm = 1 inch) 5.4 ft 12 in 1 ft = 1646 mm Sig. Fig mm ftmm 2.54 cm 1 in 10 mm 1 cm

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Accuracy and Precision, continued Problem Example - RECORD in notes before checking. A student measures the mass and volume of a substance and calculates its density as 1.40 g/mL. The correct, or accepted, value of the density is 1.30 g/mL. What is the percentage error of the student’s measurement? Section 3 Using Scientific Measurements Chapter 2

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Accuracy and Precision, continued Sample Problem C Solution Section 3 Using Scientific Measurements Chapter 2 = 7.69% Sig.Fig.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Accuracy and Precision, continued Error in Measurement Some error or uncertainty always exists in any measurement. skill of the measurer conditions of measurement measuring instruments Section 3 Using Scientific Measurements Chapter 2

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Significant Figures Significant figures in a measurement consist of all the digits known with certainty plus one final digit, which is somewhat uncertain or is estimated. The term significant does not mean certain. Section 3 Using Scientific Measurements Chapter 2

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Sig. figs. in a measurement include the known digits plus a final estimated digit Section 3 Using Scientific Measurements Chapter 2

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Significant Figures Chapter 2 ch02/sec03/vc02/hc602_03_v02fs.htm

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Significant Figures, continued Determining the Number of Significant Figures Section 3 Using Scientific Measurements Chapter 2

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Rules for Determining Significant Zeros Chapter 2 2/sec03/vc03/hc602_03_v03fs.htm

, C. Significant Figures Counting Sig Fig Examples , sig figs 3 sig figs 2 sig figs

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Significant Figures, continued Sample Problem D How many significant figures are in each of the following measurements? a g b cm c. 910 m d L e kg Section 3 Using Scientific Measurements Chapter 2

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu a.28.6 g Section 3 Using Scientific Measurements Chapter 2 Significant Figures, continued Sample Problem D Solution By rule 4, the zero is not significant; there are 2 significant figures. c. 910 m By rule 4, the zero is significant because it is immediately followed by a decimal point; there are 4 significant figures. b cm There are no zeros, so all three digits are significant.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu d L Section 3 Using Scientific Measurements Chapter 2 Significant Figures, continued Sample Problem D Solution, continued By rule 2, the first three zeros are not significant; by rule 3, the last three zeros are significant; there are 5 significant figures. e kg By rule 2, the first two zeros are not significant; by rule 1, the third zero is significant; there are 4 significant figures.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu SIG. FIG. PRACTICE QUESTIONS OPENER #10 - TUESDAY, JANUARY 22, 2013 Write the number and the answer. Pick up calculator.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu SIG. FIG. ANSWERS - CHECK WORK

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Significant Figures, continued Rounding Section 3 Using Scientific Measurements Chapter 2

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Rules for Rounding Numbers Chapter 2 x/student/ch02/sec03/vc04/hc602_03_ v04fs.htm

C. Significant Figures  Calculating with Sig Figs  Multiply/Divide - The # with the fewest sig figs determines the # of sig figs in the answer. (13.91g/cm 3 )(23.3cm 3 ) = g 324 g 4 SF3 SF

C. Significant Figures  Calculating with Sig Figs (con’t)  Add/Subtract - The # with the lowest decimal value determines the place of the last sig fig in the answer mL mL 7.85 mL 224 g g 354 g → 7.8 mL → 350 g 3.75 mL mL 7.85 mL 224 g g 354 g

C. Significant Figures  Calculating with Sig Figs (con’t)  Exact Numbers do not limit the # of sig figs in the answer.  Counting numbers: 12 students  Exact conversions: 1 m = 100 cm  “1” in any conversion: 1 in = 2.54 cm

C. Significant Figures  f). (15.30 g) ÷ (6.4 mL) Practice Problems = g/mL → 18.1 g g). 18.9g g g 4 SF2 SF → 2.4 g/mL 2 SF

ASSIGNMENTS  *Have out study guide questions.  *Complete dimensional analysis problems and turn in box no later than tomorrow.  *Finish measurement questions and turn in box no later than tomorrow.  *Start computer game review to help with test; also available from home.  TEST ch.1-2 is on Thursday!

OPENER #8 - FRIDAY - 8/31/12  Opener - pre-lab sheet from yesterday side 1 only. Side 2 is homework due Tuesday.  *Pick up lab data recording sheet & procedure sheet. (2 sheets for lab)  *Pick up calculator. Have out S.GUIDE  *Picture packets (juniors - 1st block)  *CW: Measurement Lab (stations)  *TEST - THURS 9/6/12 ch. 1-2

OPENER #9- FRIDAY - 1/18/2013  Opener - sig.fig. quiz handout - turn over when done & work on DA sheet.  *Pick up lab data recording sheet & procedure sheet. (2 sheets for lab)  *CW: Dimensional Analysis w/sheet turn in when completed.  *Pick up review game sheet. See me when ready.  *Pick up calculator. Have out S.GUIDE  HW: Study guide questions  *CW: Measurement Lab (stations)  *TEST - THURS 1/24 on ch. 1-2

D. Scientific Notation - did with Bingo  Converting into Sci. Notation:  Move decimal until there’s 1 digit to its left. Places moved = exponent.  Large # (>1)  positive exponent Small # (<1)  negative exponent  Only include sig figs. 65,000 kg → 6.5 × 10 4 kg

OPENER #10 - MON SEPT 4, 2012 Pick up calculator & computer & handout.  1. 2,400,000  g  kg  3.7  km   10 4 mm 2.4  10 6  g 2.56  kg km 62,000 mm Rewrite each to scientific notation or standard form. Turn in side 2 of opener sheet from Friday. (conversion questions). HW: Measurement Lab due tomorrow.

ASSIGNMENTS MON  *Turn in the homework conversion from Friday (back of opener) IN BOX.  CW/HW: Computer Lab Activities Game due tomorrow if not finished in class.  HW: Measurement Lab due tomorrow.  HW: Study for TEST on THURSDAY due to School Pictures tomorrow  Ch.1-2 Test is Thursday! Be well prepared & Make an A!

D. Scientific Notation  Calculating with Sci. Notation (5.44 × 10 7 g) ÷ (8.1 × 10 4 mol) = 5.44 EXP EE ÷ EXP EE ENTER EXE = = 670 g/mol= 6.7 × 10 2 g/mol Type on your calculator:

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Stop here and play BINGO GAME ACTIVITY HW: Study Guide Questions due on Friday. Get out a sheet of paper and make a 5 x 5 grid. (5 rows and 5 columns)

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu OPENER #11 - WEDNESDAY, SEPTEMBER 5, How many significant figures do these have? A. 200 mL B mL C mL D mL 2. Calculate the Percentage Error for a mass measurement of 17.7 g given that the correct value is 21.2 g. Show your work even if using calculator. CW: Turn in Measurement Lab from last Friday data sheet, conversion calculations with T-charts showing dimensional analysis and pre-lab with instruction sheet stapled together IN BOX. *Also turn in conversion homework with opener #9 sheet if not done yesterday. *CW: Compete 3.1 Notes & Computer Review Activity Games TEST is tomorrow over ch BE WELL PREPARED!!!!!

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu THURSDAY, SEPTEMBER 6, 2012 *Have out openers, Notes packets ch.1 & 2, and Bingo Game, quick salt-egg water lab questions, and computer review game sheet to turn in. I will pick these up and staple while you get ready to start your test. *Have out notebook sheet of paper with your name on it and TEST ch.1-2 Part 2 as title. *Have out pencil or blue/black pen and calculator. *Pick up computer and log-in to the podcast page. *Download test & reference sheet - #1-60 on computer AND #61-75 on notebook paper.