2. Chemical Quantities

3. We’re going to “tally” some bananas 6 ft 7 ft 8 ft Bunch!

4. Assume you have 1 boatload of bananas. Lets say 1 boat can hold 156 bananas. And the bananas are in bunches that hold 24 bananas each. Answer the following questions…

5. Banana Boat How many single bananas are there in the boat? You have 156 single bananas. How many dozen bananas are there? You also have 13 dozen bananas. How many bunches of bananas are there? You also have 6.5 bunches of bananas. Notice that each of the measurements above represent the same number of bananas. There’s simply more than one way (more than one unit) to represent this amount of bananas. The point: In chemistry there will be several ways to represent the same amount of a chemical. You will need to be able to convert from 1 unit to any other.

6. A Closer Look at the Banana Boat 1 boat load = 156 bananas 1 dozen = 12 bananas 1 bunch = 2 dozen Chances are you did the banana boat math in your head. Lets have a look at how it actually is calculated- this idea will soon apply to chemicals in a chemical reaction that you will not be able to do in your head.

7. Questions 1-a closer look How many single bananas are in the boat?… 156 This is the proper way to show this calculation… 1 boat of bananas X Boat of bananas This will cancel the unit of BOAT of banana bananas 1 156 Boat of bananas is now canceled What remains- is exactly what we were looking for! Finally do the math Answer = 156 bananas This is what we are looking for. 1 boat load = 156 bananas 1 dozen = 12 bananas 1 bunch = 2 dozen

8. Question 2- A closer look How many dozen bananas are in this same boat? 1 boat of B X Boat of B Single Bs 1 156 X Dozen Bs 12 1 Single Bs = What units must be on bottom to cancel what remains so far? What units are we looking for? DO NOT!.... Do not insert ANY numbers until you have units on both top and bottom!!!!!!!!!!!! What is the number relationship between the units on the top and bottom? What remains- is exactly what we were looking for! Do the math… Answer= 13 dozen bananas 1 X 156 x 1 1 X 12 () = 1 boat load = 156 bananas 1 dozen = 12 bananas 1 bunch = 2 dozen

9. How many bunches of bananas are there on this same boat? 1 boat BX boat B single B 1 156 X dozen B 12 1 single B dozen B bunch B 2 1 X = Question 3- A closer look 1 boat load = 156 bananas 1 dozen = 12 bananas 1 bunch = 2 dozen 1 X 156 x 1 X1 1 X 12 X 2 () = Answer= 6.5 bunches of B

10. Beyond Bananas Equivalents = items that are equal to each other in amount/quantity. You fill in the equivalents for the following… 1 min= seconds 1 hr= min 1 day = hrs 1 year = days 60 60 24 365

11. Movie Trivia! Which of the following was the longest movie? D. Gone With the Wind A. Pearl Harbor E. The God Father C. The sound of music B. Gods and Generals

12. 175 min A BC D E 175 min 229 min 183 min 220 min

13. 229 minX min hr 60 1 = How Long? How long in hrs is this longest movie? Answer= about 3.82 hrs

14. How long is 4.5 days in minutes? 6480 mins= answer- be sure you can get it.

15. Standard Scientific Notation (SSN) We will be dealing with very large numbers as well as very small numbers… 3 000 000 000 000 3 x 10 12.00000004784.78 x 10 -8 4.578 x 10 -4 7.8 x 10 3.0004578 7800

16. Rounding Final Answers (Using Significant Figures)

17. Significant Figures/Digits Which numbers in a measurement are significant? Ex..045 g of Au How to determine which numbers are significant figures… THE UNITED STATES Method Draw the US- the number inside Label Pacific – Atlantic P= decimal is present A= decimal is absent

18. Decimal Present: Rules If a decimal is PRESENT… 1) Start from the P side and approach the number (the left) 2) Keep going until you hit the first non- zero number- stop before that number. 3) This first non-zero digit and all numbers after are significant digits! (including zeros)

19. How many Sig. Figs.?.0034 g Ag has… 2 sig. figs. 224.00 mg Ca… 5 sig. figs..004000 L of oxygen… 4 sig. figs. 234.0 g Sr… 4 sig figs.0000000000003 g Ti… (12 zeros) 1 sig. fig.

20. Decimal Absent: Rules If a decimal is Absent… 1) Start from the A (the right) side and approach the number 2) Keep going until you hit the first non- zero number- stop before that number. 3) This first non-zero digit and all numbers to the left are significant digits! (including zeros)

21. How many Sig. Figs.? 234 g Ag has… 3 sig. figs. 2240 mg Ca… 3 sig. figs. 43600 L of oxygen… 3 sig. figs. 200000000 mg Ti… (8 zeros) 1 sig. fig.

22. Rounding Answers for Multiplication and Division Problems Rule: The final ROUNDED answer must have the same number of significant figures as the measurement with the FEWEST sig figs in it. Ex. 23.40 m x 1.4 m = Cal= 32.76 R= 33 4 sig figs2 sig figs SSN= 3.3 x 10 1 m 2

23. Try a few Ex..00340 m x.078 m = Cal=.0002652 OR 2.652 X 10 -4 R=.00027 Or 2.7 X 10 -4 SSN = 2.7 x 10 -4 m 2 Ex. 34050 g x 7860 L = Cal= 267633000 R= 268000000 SSN = 2.68 x 10 8 gL

24. More Practice Ex. 7.18 g/ 2.300 g = Cal= 3.12173913 R= 3.12 SSN = 3.12 x 10 0 (no units) Ex. 34.00 m /.0200 g = Cal= 1700 (2 sig. figs. currently) R= (Can’t do it without SSN) SSN = 1.70 x10 3 m/g

25. Round each cal. to 2 sig figs, then 3 sig figs A) 3.2354 g B) 3.45 g C) 67 g D) 4.5 g E) 2395 g F) 749399 g G) 749671 g H).00432 g I).03476 g J) 3496.983 g K).088654 g R= 3.2 gR= 3.24 g R= 3.5 gR= 3.45 g R= 67 gR= 67.0 g R= 4.5 gR= 4.50 g R= 2400 gR= 2.40 x 10 3 g R= 750000 gR= 749000 g R= 750000 gR= 7.50 x 10 5 g R=.0043 gR=.00432 g R=.035 g R=.0348 g R= 3500 g R= 3.50 x 10 3 g R=.089 gR=.0887 g

26. Adding and Subtracting measurements Rule: The final ROUNDED answer must have the same number of digits PAST THE DECIMAL as the measurement with the Fewest Past the Decimal. DO NOT TRY TO USE SIG. FIGS. IN ANY WAY.

27. Bellwork: Date: Mini starts 3 min after bell.

28. Sig figs, Rounding, and SSN mini/warm-up Identify how many significant figures 1).2650 g 2) 450 N 3).00021 m/s 4) 8.10 m 5)1050 L Round each of the following to 3 sig figs. 6) 1233 m _________7).01234m _______8) 67978 m _________ 9) 23 m _________ 10).78944 m _________ [Multiply/divide] the following / cal=, R=, and SSN= 11).234 g x.140 g 12)4.80mm x 2.500L 13) 214.5 kg/.032 L 14) 200.0 N x 16.0 N

29. Sig figs, Rounding, and SSN mini Identify how many significant figures 1).2650 g 2) 450 N 3).00021 m/s 4) 8.10 m 5)1050 L Round each of the following to 3 sig figs. 6) 1233 m 7).01234 m 8) 67978 m9) 23 m10).78944 m [Multiply/divide] the following / cal=, R=, and SSN= 11).234 g x.140 g 12)4.80mm x 2.500L 13) 214.5 kg/.032 L 14) 200.0 N x 16.0 N Cal=.03276 R=12.0Cal= 12 Cal= 6703.125 Cal= 3200 R=.0328 R=6700 R=can’t/SSN 11) SSN= 3.28 x 10 -2 g 2 12) SSN= 1.20 x 10 1 mmL 13) SSN= 6.7 x 10 3 kg/L 14) SSN= 3.20 x 10 3 N 2 6) 1230 m 7).0123 m 8) 6.80 x 10 4 m 9) 23.0 m 10).789 m 4 2 2 3 3

30. Chemical Equivalents Here is a list of some typical units used in chemistry. 1) Mass- a measure of the amount of matter in something. Mass is measured in grams 2) atoms- the smallest unit of an element 3) molecules- the smallest unit of a covalent compound 4) Formula units- the smallest unit of an ionic compound. 5) Volume- How much space a chemical takes up. The volume of gases will be measured in Liters. The volume of solids will be measured in cm 3 6) Moles- TBA

31. Representative Particles: a visual aid Pure substances (non-bonded/solo) Ionic compounds (bonded:contain a metal) Covalent compounds (bonded: all non-metals) Fe, Au, Ne, S NaCl, FeCl 2, Li 2 O H 2 0, N 2, CO 2, O 2 RP= atoms RP= formula units (FU) for short RP= molecules (mc) for short (mc) for short examplesexamples Smallest amount you can have

32. Representative Particles Representative particle (RP)- the smallest amount you can have of a chemical. Example 1: Atoms: A nugget of gold: Note that in this case gold is a pure substance- that is there are no other elements present. If you cut this pile until you had only 1 gold left you would have one ATOM of gold Thus the RP for pure gold is an ATOM.

33. Representative Particles Example 2: Molecules: A glass of water: If you pour off some water, you’re pouring off billions of H 2 0s. If you poured it all off until you had only 1 H 2 0 left- you would have 1 MOLECULE of water. Thus the RP for the covalent compound water is a molecule.

34. Representative Particles Example 3: Formula units: A packet of table salt (NaCl): Each individual grain of salt in the packet is made of millions of NaCls. If you cut this grain away more and more until only one NaCl remained… you would be left with one formula unit of NaCl. Thus the RP for the ionic compound salt is a formula unit.

35. Meet the Mole?! A very common unit of measurement in chemistry is the mole. How much is a mole? How much is a dozen? 12 of anything In the same way, a mole is exactly 6.02 X 10 23 singles units of anything of a substance… ?

36. 1 mole of zinc Let’s consider…

37. 1 mole of zinc Let’s consider… First lets actually see what 1 mole of zinc looks like… How do I know how much zinc is considered to be “1 mole is for zinc?” Use the periodic chart to find out…. The mass shown there (we called it the average atomic mass before) is how much we need in GRAMS. So we need 65.39 grams.

38. 1 mole of zinc Let’s consider… This amount of zinc (the amount the the mass of the formula)…. Is called the gram fomula mass It is also called the molar mass. Why? Because 1 mole of zinc weighs this much ! (65.39 grams) How much would I need to get 1 mole of gold? 196.97 g of gold= 1 mole of gold

39. The Big Picture… GFM How much does a mole weigh/mass? It depends on the substance! 1 mole= Zinc= 65.39 g Zn Gold= 196.97 How much mass is 1 mole of CO 2 ? 44.12 C-12.01 (2x) O= 16.00

40. Gram Formula Mass (GFM) How much does a mole weigh? Does a dozen bananas and a dozen pencils weigh the same? Likewise, each element or compound has a different mass, so the weight of a mole of each will vary. A chemical’s GFM (gram formula mass) represents the weight of 1 mole of the chemical in question. GFM is the mass of the formula of a chemical- you will use the periodic chart and calculate it.

41. Ex. How much does 1 mole of gold weigh? 196.97 g Au = 1 mole of Au (always round to the hundredths place) “196.97” is gold’s GFM How much does a mole of water weigh? Hint: Water has 2 H and 1 O. 1.01 + 1.01 +16.00= 18.02g is water’s GFM= 1 mole H 2 0 Or 1 mole of water weighs 18.02g! Find Magnesium chloride’s GFM (Watch your formula!): 24.31 + 35.45 + 35.45= 95.21 g MgCl 2 = 1 mole of MgCl 2

42. Bellwork: Date: Find the GFM for following… 1 mole of Chromium = _____ grams of Cr 1 molar mass of Aluminum chloride= ____ grams of _______(formula) The GFM for carbon dioxide is ______ grams. The GFM for iron IV oxide is _______ grams. The Molar mass of Iodine? Careful!______ 133.33 52.00 AlCl 3 44.01 87.85 253.80 g

43. A mole of any gas… C) a mole of any gas always takes up 22.4 liters of space at standard temperature and pressure (STP). If the Temp is 0 degrees C and the pressure is 1 atmosphere--- conditions are considered “STP”. We will assume conditions are STP unless told otherwise. Ex. 1 mole of H 2 = 22.4 L of H 2 1 mole of Ne = 22.4 L of Ne 1 mole of CO 2 = 22.4 L of CO 2 } This is true at STP only

44. Converting Chemical Quantities Equivalents 1 mole = atoms, molecules, or FU (RPs) 1 mole = 1 mole = liters of gas at STP 6.02 x 10 23 GFM of the chemical (see PC) 22.4

45. Chemical Equivalents Consider this amount of gold Assume you have 2 moles of gold. 1 mole of gold = 6.02 X 10 23 atoms of gold (single units) 1 mole of gold = 196.97 grams of gold (mass)

46. Chemical Equivalents If this is 2.0 moles of Au, how many grams would it weigh? 2.0 mol Au X mol Au g Au 1 196.97 = Cal=393.94 R=390 SSN=3.9 x 10 2 g Au ????

47. 888.0g Chemical Equivalents If this lump of Au has a mass of 888g, 888 g Au X g Au mol Au 196.97 1 X Atoms Au 1 6.02 x 10 23 mol Au = Cal= 2.713997055 x10 24 R=2.71 x10 24 SSN= 2.71 x10 24 atoms Au how many atoms are in the sample? This should be a big number!

48. Please See…..the online VIDEO help I have made. It will walk you through each problem of the first two practice sheets. The movies are online in the chemical quantities folder.

49. Let’s try a few… How many grams would 2.5 moles of gold weigh? How many Liters (STP) would 5.0 moles of Neon gas be? How many atoms of gold are in a nugget that has a mass of 23.04 grams?

50. A few more… 4.65 x 10 23 molecules of oxygen would be how many moles? ** 455.3 grams of aluminum chloride (careful with that formula!) has how many Formula units in it?