Chemistry 101. Dr. Lucio Gelmini Room 5-132A

Transcription

1 Chemistry 101 Dr. Lucio Gelmini Room 5-132A

2

3

4

5

6

7

8

9

10 Welcome to CHEM 101 Grant MacEwan University September 2011

11 Welcome to Day One! Textbook Tax Credit-Get your money back! Your course textbook options Logging into OWL for your homework Accessing your e-book

12 Did you know that you can claim $65 for each month you qualify for the full-time education amount? or Textbook Tax Credit $20 for each month you qualify for the part-time education amount? You can claim the textbook amount (right on your tax return!) if you are eligible to claim the education amount (and can support, with documentation, your enrolment at a post-secondary institution).

13 YOUR COURSE PACKAGE IS AVAILABLE IN THE BOOKSTORE NOW! Electronic only option: 24 month OWL access code w/ ebook, Macewan bookstore. $69.95 Textbook option: Zumdahl Chemical Principles 6ed, Student solutions manual & OWL access code w/ ebook, $ ATTN: Dr. Llano s sections, you will also require a Turningpoint clicker, available at the campus bookstore.

14 How to Register for the OWL System

15 How to Register FIRST: Get an access code. Three ways to purchase: Packaged with the purchase of a new textbook Purchased separately from the book store Purchased online. Go to Access codes are 25 characters long and look like this: kg609-qkj3y-2kd4k-h3kvq-hv5d4 Go to:

16 Select Your Course and Click Register

17 Select Your Textbook Click on the name of your Textbook

18 Select Your School Select your school from a list

19 Select Student Registration Click on the blue arrow under Student Registration

20 Select the Course/Section you are in Make sure you select the correct section

21 Complete the Form Enter Access Code here OR Choose the 14 day trial

22 Confirm info and click continue

23 Agreement Click I AGREE after reading.

24 Complete the registration process At the successful registration page, choose the Login Page

25 Enter Login and Password Enter Login and password you chose during registration Click here if you ve forgotten your password

26 To Log In Throughout the Semester If you forgot to bookmark the login page or ever need to get back to it: Go to: Select your and choose Log in You ll be prompted to then choose your course and school

27 Choose Your Class Click on the class you are in

28 Your Course Homepage If you used the 2 week grace period, it tracks when you must enter a code

29 See your current assignments

30 For Student Support Click here to contact Technical Support

31 Got Questions!? Come visit us! We will be hosting student office hours for you to come and ask us questions about OWL. Room Friday, September 9 10:30 AM-12:30 PM Room Tuesday, September 13

32 Thank You Have a Great Semester!

33 Goals for this class and beyond To develop chemical intuition and curiosity To acquire the knowledge and knowhow for solving chemistry problems To learn how to learn, particularly in a science classroom

34 Review topics Definitions Scientific problem solving Math review Uncertainty in measurement and significant figures

35 What is chemistry? Chemistry is the science of matter and its transformations Goals: to better understand the nature of matter to predict and control its behavior to develop new combinations, processes, and applications

36 Scientific method Observations Qualitative, quantitative, or semi-quantitative Hypothesis Initial opinion or guess Experiments Rational, repeatable investigations Verification/communication Further investigation Formulation of laws, theories, and/or models

37 Thinking chemically Problem solving: repetition, practice, and experience Educated guessing Trial and error

38 Central idea in chemistry Macroscopic properties and behavior result from submicroscopic properties Observable changes Unobservable causes

39 Matter: Definitions has mass and volume Properties: characteristics that give each substance a unique identity Physical: shows these by itself without interacting with another substance color, state (s, l, g), density, Chemical: substance shows these as it interacts with or transforms into other substances reactivity, flammability,

40 Physical vs. chemical change Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Physical change Chemical Change Ice (solid water) liquid water Water hydrogen + oxygen

41 Physical states of matter

42 Example physical & chemical properties of copper Shiny Reddish Malleable Conductive slowly reacts in moist air reacts with nitric acid d = 8.95 g/cm 3 melts at 1083 C boils at 2570 C slowly forms a deep-blue solution in aqueous ammonia

43 Conceptual chemical reaction A + B C + D Reactants Products Forward and reverse direction Depending on the process or reaction: Energy can be absorbed or released Energy change can be large or small

44 Chemical reaction: Examples Methane (natural gas) combustion releases heat CH 4 (g) + 2 O 2 (g) CO 2 (g) + 2 H 2 O(g) Physical transformation: Water boiling to form steam requires energy H 2 O(l) H 2 O(g)

45 Problem Solving Identify problem Given and desired values Plan Find known relationships Set up Conversion/unit cancellation Calculate solution Number and units

46 Values: Quantitative science number + unit Units: chemistry uses SI units (International System of Units) the metric system Math: go through appendix 1 (math review) and 2 (units/calculations)

47 Exact vs. inexact numbers Exact: defined or counted have as many sig.figs. as needed no uncertainty do not limit #sig.figs. in answer Inexact: come from measurements have associated uncertainty (from measurement) may limit #sig.figs. in answer

48 Precision Precision vs. accuracy how close repeated measurements are to each other reproducibility Accuracy how close measurements are to actual (real) value correctness Precise Not Accurate Better Accuracy Not Precise Precise Accurate

49 9.90 Mass of Water measured values are all above or below real 10.10value can be corrected for (in theory) Mass (g) Precision vs. accuracy Systematic error Trial Random error Mass of Water measured values are scattered above and below real value Mass (g) can 10.00only be minimized through more precise measurement/equipment Trial

50 Calculations and meaning Significant Figures Number of decimal places in a reported value: should reflect the precision of the measurement depend on scale/divisions on measuring device cm ± 0.1 cm to 1/10 of a cm cm ± 0.01 cm to 1/100 of a cm

51 Rules for Determining Significance All non-zero digits are significant Zeroes may or may not be significant Leading: NOT significant g has 2 sig.figs. Buried: ARE significant g has 3 sig.figs. Trailing: depends on if a decimal point is present with. significant g has 3 sig.figs. without. who knows? 230 g has 2 or 3 sig.figs. Choice express/convince yourself

52 Examples ml g g s km 15.0 cm 3 Scientific notation removes any ambiguity: Example: 1000 m m 4 sig.figs. to ±1 m m 3 sig.figs. to ±10 m m 2 sig.figs. to ±100 m

53 Calculations and significant figures Addition & subtraction: Round answer to least precise decimal place 83.5 ml ml ml = ml Multiplication & division: ml ml ml = ml Round answer to least number of sig.figs. 9.2 cm 6.80 cm cm = cm 3 = 23 cm 3

54 Rounding Round at the end of all steps in a calculation If the digit removed is more than 5, the preceding number increases by 1, hence, g 1.35 g If the digit removed is less than 5, the preceding number is unchanged, hence, g 1.34 g If the digit removed is 5, the preceding number increases by 1 if it is odd and remains unchanged if it is even g 1.34 g g 1.34 g

55 Example cm cm All measured #s cm 2 = Units are kept or cancelled cm cm cm 2 = cm cm 2 = cm Defined relationship 1 m cm = m = cm m

56 mg cm Example 2 ( 1 g ) 1000mg = 3 Measured #s Defined relationship mg cm ( 1g ) mg = 48.0 g cm 3 = 4.16 g cm 3

57 SI Base Units Base quantity Name Symbol length meter m mass kilogram kg time second s temperature kelvin K amount of substance mole mol luminous intensity candela cd electric current ampere A First 5 most important in this class

58 Derived units Combination of base units Examples: Area: two dimensional length m m = m 2 Volume: three dimensional length m m m = m 3 Speed: length and time m / s Work/energy: mass, length, acceleration kg m m/s 2 = = J And so on

59 Exponential Name Symbol yotta Y zetta Z exa E peta P tera T giga G mega M kilo k hecto h deka da Prefixes Express huge range of values in more manageable ways Exponential Name Symbol deci d centi c milli m micro µ nano n pico p femto f atto a zepto z yocto y Bigger than base Smaller than base

60 Using prefixes Exponential replaces prefix and vice versa More coming on conversion problems 1 kg = g 4.11 nm = m

61 Using relationships in conversion problems What is the price of 325 cm of copper wire that sells for $0.15/ft? Find desired look for words like what is, calculate, find, Target: price ($) To what is target compared look at other end of the question Given: 325 cm wire

62 Set up problem to cancel units Price: in $ Length: in cm Length-price relationship: in $ and feet Find conversion factors (may need to look up) (Given on test) 1 in = 2.54 cm (exactly) 1 ft = 12 in (exactly) 1 ft = $0.15(exactly) Set up problem to cancel units Perform math check value and units 1 in 1 ft $ cm = $ cm 12 in 1 ft

63 More How many sodium atoms would it take to form a line 1 foot long (1 foot = m) if the diameter of a sodium atom is about 186 picometers? The symbol for sodium is Na. Target: # Na atoms Given:1 foot Conversion factors: 1 foot = m 1 pm = m 1 Na atom = 186 pm Calculation: m 1 pm 1Naatom 1 ft = ft m pm Naatoms

64 Density mass and volume Density: ratio of mass to volume mass density = or d = volume m v Units: g/ml, g cm 3, g/l, Densities of common substances: Substance Physical State Density (g/cm 3 ) Hydrogen Gas Oxygen Gas Grain alcohol Liquid Water Table salt Liquid Solid Aluminum Solid 2.70 Lead Solid 11.3 Gold Solid 19.3 * At room temperature(20 0 C) and normal atmospheric pressure(1atm).

65 Freezing and boiling points of water

66 MOST COMMON CONVERSIONS IN CHEMISTRY g A mol A mol B g B g CO to mol CO or mol CO to g CO (periodic table converts mass to moles) 1 mol CO = g CO How about mol A mol B?

67 Mol A Mol B A few ways of doing this 1.Chemical formula H 2 O says that for every mole of H 2 O there are two moles H or one mol O 1 mol H 2 O = 2 mol H = 1 mol O How about CuSO 4 5 H 2 O Conversion factors?

68 Mol A Mol B A few ways of doing this 2.Chemical reaction (balanced) 2 Al(s) + 6 H + (aq) 2 Al 3+ (aq) + 3 H 2 (g) 3 mol H 2 = 6 mol H + = 2 mol Al = 2 mol Al 3+ USE COEFFICIENTS IN BALANCE REACTION