I II III Welcome to Chemistry 116!

 Work to be turned in will only be accepted during the first 10 minutes of lab, or will be considered late  Work Later then one week will not be accepted, unless approved by me.  If absent from lab 20 point deduction from the lab write up, you can complete the pre-lab questions and post lab questions for credit  More then two absences, you will automatically drop a grade  At the end of the lab, all materials need to be put away lab benches cleaned or 10 points will be deducted per lab Grading Policy

Grades  Short quiz worth 10 points  lab report will include data, graphs and calculations worth 20 points  Post lab questions worth 10 points.  Practical exam will be given at the end of the semester worth 100 points.

How to print out notes  Go to file, click on print, look for print what change from slides to handouts; then adjust how many you want per page.  Also change color to pure black & white.

I II III I. Using Measurements CH. 1 - MEASUREMENT

B. Percent Error  Indicates accuracy of a measurement your value book value

B. Percent Error  A student determines the density of a substance to be 1.40 g/mL. Find the % error if the accepted value of the density is 1.36 g/mL. % error = 2.9 %

C. Significant Figures  Indicate precision of a measurement.  Recording Sig Figs  Sig figs in a measurement include the known digits plus a final estimated digit 2.35 cm

C. Significant Figures  What you see + a guess ml

C. Significant Figures  Counting Sig Figs  Count all numbers EXCEPT:  Leading zeros  Trailing zeros without a decimal point -- 2,500

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

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. Adding or subtracting Significant Figures  The result has the same number of decimal places as the measurement with the of decimal places mL + 4 mL 7 mL 22.4 g g 35.9 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 5. (15.30 g) ÷ (6.4 mL) Practice Problems = g/mL  18.1 g g g g 4 SF2 SF  2.4 g/mL 2 SF

D. Scientific Notation  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

D. Scientific Notation 7. 2,400,000  g kg 9.7  km  10 4 mm Practice Problems 2.4  10 6  g 2.56  kg km 62,000 mm

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:

E. Proportions  Direct Proportion  Inverse Proportion y x y x

Lab Part A on page 11  A Length of book correct sig figs- measure in Cms and convert into mm, m, and inches Show all work Determine area of book

Lab Part B on page 11  Graduated cylinder  Large test tube correct sig figs- measure in mls

Due next week  Prepare for quiz  Wst on measurements 1