1. Do Now: 1. Check HW #4 2. Chemistry reference Tables (CRT) out on desk Agenda: 1.HW Qs 2.Review of Sci notation and Sig Fig. /check 3. Dimensional Analysis notes and practice 4. Ticket to Leave U1D9: HOW DO WE CONVERT FROM ONE UNIT TO ANOTHER ALGEBRAICALLY?

2. PERIOD 2 ONLY TAKE OUT PRACTICE PACKET Number Scientific Notation 250. 200 000 0.000 55 602 300 000 000 000 000 000 000 0.000 000 000 000 000 000 160 2 A) Convert each of the following into scientific notation:

3. 3 Scientific NotationStandard Decimal Notation 7.982 X 10 11 7.02 X 10 -4 2.030 X 10- 18 4.3 X 10 -5 B) Convert each of the following into standard decimal notation:

4. C) Ksp is a measurement of the solubility of a salt. The larger the value of Ksp is, the more salt can dissolve in water. 1)4.3 X 10 -6 2) 5.7 X 10 -7 3) 9.8 X 10 -8 4) 3.2 x 10 -9 a) Which of the following Ksp values would indicate the salt with the highest solubility? _______ b) Which of the following Ksp values would indicate the salt with the lowest solubility? _______ c) Explain how you answered a and b. 4

8. Yes, algebra is actually used in the real world to do stuff! Like the stuff you’re about to learn here. USING UNITS TO SOLVE PROBLEMS

9. WHAT DO YOU KNOW? EXPLAIN HOW to rearrange the equation q = m C  T to solve for  T, ending with a correctly rearranged equation.

10. PROBLEM-SOLVING STRATEGY Identify the GIVEN and the TARGET Write down the GIVEN, including the units Multiply or divide the GIVEN by a CONVERSION FACTOR that will give you your TARGET. Use the units to decide whether to multiply or divide. Record your TARGET, including units.

11. EXAMPLE OF CONVERSION How many minutes are there in 2.3 hours? GIVEN: 2.3 hoursTARGET: minutes CONVERSION FACTOR: 60 minutes/hour 2.3 hours 60 minutes/hour To cancel out hours, MULTIPLY. X= 138 minutes Round your answer to the number of sig figs in your measurement. The conversion factor is NOT a measurement so sig figs don’t apply. 140 minutes

12. EXAMPLE OF CONVERSION How many feet are there in 34.3 inches? GIVEN: 34.3 inchesTARGET: feet CONVERSION FACTOR: 12 inches/foot 34.3 inches 12 inches/foot To cancel out inches, DIVIDE. /= 2.8583333 feet Round your answer to the number of sig figs in your measurement. The conversion factor is NOT a measurement so sig figs don’t apply. 2.86 feet

13. EXAMPLE OF CONVERSION How many nickels are there in $42.25? GIVEN: 42.25 dollarsTARGET: nickels CONVERSION FACTOR: 20 nickels/dollar 42.25 dollars 20 nickels/dollar To cancel out dollars, MULTIPLY. X= 845 nickels Round your answer to the number of sig figs in your measurement. The conversion factor is NOT a measurement so sig figs don’t apply. 845.0 nickels

14. METRIC CONVERSIONS Look up Reference Table C. Add the following to the table: Metric system: uses prefixes to stand in for powers of ten of measured units 45 thousand grams = 45 kg 32 thousandths of a gram = 32 mg

15. CREATING METRIC CONVERSION FACTORS Write down the GIVEN and TARGET. Write above it the FACTOR for the units of each. Take the difference in power of ten between the two factors. This is the conversion factor, in terms of powers of ten. Smaller unit / larger unit How many cm in 45.2 km? given target 10 3 10 -2 10 5 difference 100000 cm/km =

16. CREATING METRIC CONVERSION FACTORS Write down the GIVEN and TARGET. Write above it the FACTOR for the units of each. Take the difference in power of ten between the two factors. This is the conversion factor, in terms of powers of ten. Smaller unit / larger unit How many nm in 18.9 m? given target 10 0 10 -9 10 9 difference 1 000 000 000 nm/m =

17. CREATING METRIC CONVERSION FACTORS Write down the GIVEN and TARGET. Write above it the FACTOR for the units of each. Take the difference in power of ten between the two factors. This is the conversion factor, in terms of powers of ten. Smaller unit / larger unit How many dm in 2.33  m? given target 10 -6 10 -1 10 5 difference 100 000  m/dm =

18. CREATING METRIC CONVERSION FACTORS Write down the GIVEN and TARGET. Write above it the FACTOR for the units of each. Take the difference in power of ten between the two factors. This is the conversion factor, in terms of powers of ten. Smaller unit / larger unit How many m in 1.73 km? given target 10 3 10 0 10 3 difference 1000 m/km =

19. PUTTING IT TOGETHER A chemical reaction takes 0.000350 seconds. How many msec is this? giventarget 10 -3 10 0 10 3 difference 1000 msec/sec = PUTTING TOGETHER THE CONVERSION FACTOR 0.000350 sec 1000 msec/sec To cancel out sec, MULTIPLY. X = 0.35 msec Round your answer to the number of sig figs in your measurement. The conversion factor is NOT a measurement so sig figs don’t apply. 0.350 msec USING THE CONVERSION FACTOR

20. PUTTING IT TOGETHER A batch of medication has a volume of 2.30 dL. How many mL is this? given target 10 -3 10 -1 10 2 difference 100 mL/dL = PUTTING TOGETHER THE CONVERSION FACTOR 2.30 dL 100 mL/dL To cancel out dL, MULTIPLY. X = 230 mL Round your answer to the number of sig figs in your measurement. The conversion factor is NOT a measurement so sig figs don’t apply. 230. mL USING THE CONVERSION FACTOR

21. PUTTING IT TOGETHER 9.34 cg of KCl are needed for a reaction. Your balance measures in g. How many g of KCl need to be weighed? given target 10 0 10 -2 10 2 difference 100 cg/g = PUTTING TOGETHER THE CONVERSION FACTOR 9.34 cg 100 cg/g To cancel out cg, DIVIDE. / = 0.0934 g Round your answer to the number of sig figs in your measurement. The conversion factor is NOT a measurement so sig figs don’t apply. 0.0934 g USING THE CONVERSION FACTOR

22. PUTTING IT TOGETHER The distance between two points is 54.3 km. How many dm is this? giventarget 10 -1 10 3 10 4 difference 10 000 dm/km = PUTTING TOGETHER THE CONVERSION FACTOR 54.3 km 10 000 dm/km To cancel out km, MULTIPLY. X = 543 000 dm Round your answer to the number of sig figs in your measurement. The conversion factor is NOT a measurement so sig figs don’t apply. 543 000 dm USING THE CONVERSION FACTOR

23. YOUR TURN! (CONVERSION WS AND HW #5) For each of the problems on p. 24: 1)Identify the given and target 2)Write the factors 3)Create the conversion factor 4)Multiply or divide the given by the conversion factor so that the units cancel out to give you your target units 5)Round your answer off properly ALL UNITS NEED TO BE INCLUDED. IF THERE IS A NUMBER, THERE MUST BE A UNIT AFTER IT.

24. TICKET OUT: ON INDEX CARD Name: Date: Period : Explain, step by step, how to convert 43.2 mg to kg, ending with the correctly converted answer.

25. TO COMPLETE: EXTRA CREDIT (+5), to be given if all work is shown with all units and all answers rounded off properly DUE Friday Name:_______________________ Dimensional Analysis Practice Below are interesting statistical facts that you will have to do some dimensional analysis with. You will need to show the set up as well as the solution for each of the problems. Make sureall answers are in scientific notation and to the correct number of sig figs. Ex)1.14 million paper bags are used in U.S supermarkets every hour. How many bags a second is that? (1.14 x 10 6 bags/hr) x (1hr/60 min) x (1min/ 60 sec) =316.666667 bags/sec  317 bags/sec 1) The speed of light is roughly 3.00 x 10 8 m/s. What is the speed of light in km/s? 2) The average distance of earth from the sun is 1.50 x 10^8 km. What is that in centimeters? 3)How far would you have traveled (without seeing the road) if you took 5.00 seconds to check a text traveling at 72 km/hr (about 45 mph) in meters? 4) On average, a facebook user spends 55 minutes per day on facebook. How many days a year is that?