Welcome to AP Chemistry

What is AP Chemistry?

• It is several things

• Equivalent of 1 year college inorganic chemistry class

• A class that will prepare you for a test– May 17

• Hard work

• A wonderful way to start the day

• Now on to the details

Rules and Procedures

• You know the basic rules but here are a few that are specific for this class

• No food drink or gum

• LATE WORK

• If you forget to bring in your homework, I will accept it ONE day late with a parent's signature, for full credit.

• I will not accepted it any later.

Rules and Procedures

• MAKE-UP WORK • It is your responsibility to make up all the

work you missed. You have the same number of days that you were absent to turn in the missing work.

• Pick up any missing work, and notes before or after class.

• If you miss a test or quiz, it must be made up outside class.

Rules and Procedures

• TARDIES• You will be allowed one ”free" tardy per

semester.• The second and every subsequent tardy will

result in a detention.• Repeated tardies will result in parent

contacts, and referrals, AND MAY RESULT IN BEING DROPPED FROM THE CLASS.

Rules and Procedures

• PASSES

• Since every minute of class time is valuable, hall passes will be given only on an emergency basis, with a limit of one per semester, except under special circumstances.

Rules and Procedures

• LAB- Because of the importance of safety in the lab, violation of laboratory safety rules and procedures may result in loss of lab privileges.

Grading

• Percentage scale

94-100% A 70-75% C

90-94% A- 65-70% C-

87-90% B+ 62-65% D+

84-87% B 58-62% D

80-84% B- 55-58% D-

75-80% C+ 0-54% F

Grading

• Quarter Grade– Tests50%– Homework/Classwork 20%– Quizzes 15%– Lab Reports 15%

• Semester Grade– 40% from each quarter– 20% on final

Extra Credit!!• Assignments will be provided approximately

mid- quarter.• They may be turned in any time until the due

date,(during the last week of the quarter)• Extra credit may be used to raise the quarter

grade by up to one letter grade.• Extra credit is meant to be extra, so it will not

be accepted if more than 10% of the other assignments are not turned in.

What you need for class

• Paper

• Pencil or pen,

• Calculator- scientific

• Book?– Not unless I let you know

• Lab Notebook

Internet Ready

• http://mrgreen.tierranet.com

• My email is tvgreen@aol.com

Why First Period?

• College chemistry labs take more than 56 minutes,

• To do those labs we will have to come early

• I will give you notice of when

Any questions?

• Lets get started

Significant figures

• Meaningful digits in a MEASUREMENT

• Exact numbers are counted, have unlimited significant figures

• If it is measured or estimated, it has sig figs.

• If not it is exact.

• All numbers except zero are significant.

• Some zeros are, some aren’t

Which zeroes count?

• In between other sig figs does

• Before the first number doesn’t

• After the last number counts iff

• it is after the decimal point

• the decimal point is written in

• 3200 2 sig figs

• 3200. 4 sig figs

Doing the math

• Multiplication and division, same number of sig figs in answer as the least in the problem

• Addition and subtraction, same number of decimal places in answer as least in problem.

More Preliminaries

Scientific Method

Metric System

Uncertainty

Scientific method.

• A way of solving problems

• Observation- what is seen or measured

• Hypothesis- educated guess of why things behave the way they do. (possible explanation)

• Experiment- designed to test hypothesis

• leads to new observations,

• and the cycle goes on

Scientific method.• After many cycles, a broad, generalizable

explanation is developed for why things behave the way they do

• Theory

• Also regular patterns of how things behave the same in different systems emerges

• Law

• Laws are summaries of observations

Scientific method.

• Theories have predictive value.

• The true test of a theory is if it can predict new behaviors.

• If the prediction is wrong, the theory must be changed.

• Theory- why

• Law - how

Observations

Hypothesis

Experiment

Law

Theory(Model)

Prediction

Experiment

Modify

Metric System• Every measurement has two parts• Number• Scale (unit)• SI system (le Systeme International) based

on the metric system• Prefix + base unit• Prefix tells you the power of 10 to multiply

by - decimal system -easy conversions

Metric System• Base Units

• Mass - kilogram (kg)

• Length- meter (m)

• Time - second (s)

• Temperature- Kelvin (K)

• Electric current- ampere (amp, A)

• Amount of substance- mole (mol)

Prefixes• giga- G 1,000,000,000 109

• mega - M 1,000,000106

• kilo - k 1,000 103

• deci-d 0.1 10-1

• centi- c 0.01 10-2

• milli- m 0.001 10-3

• micro- m 0.000001 10-6

• nano- n 0.000000001 10-9

Deriving the Liter

• Liter is defined as the volume of 1 dm3

• gram is the mass of 1 cm3

Mass and Weight

• Mass is measure of resistance to change in motion

• Weight is force of gravity.

• Sometimes used interchangeably

• Mass can’t change, weight can

Uncertainty• Basis for significant figures

• All measurements are uncertain to some degree

• Precision- how repeatable

• Accuracy- how correct - closeness to true value.

• Random error - equal chance of being high or low- addressed by averaging measurements - expected

Uncertainty• Systematic error- same direction each

time• Want to avoid this• Better precision implies better accuracy• you can have precision without accuracy• You can’t have accuracy without

precision

Dimensional Analysis

Using the units to solve problems

Dimensional Analysis• Use conversion factors to change the units• Conversion factors = 1• 1 foot = 12 inches (equivalence statement)

• 12 in = 1 = 1 ft.

1 ft. 12 in

• 2 conversion factors• multiply by the one that will give you the

correct units in your answer.

Examples• 11 yards = 2 rod

• 40 rods = 1 furlong

• 8 furlongs = 1 mile

• The Kentucky Derby race is 1.25 miles. How long is the race in rods, furlongs, meters, and kilometers?

• A marathon race is 26 miles, 385 yards. What is this distance in rods, furlongs, meters, and kilometers?

Examples• Science fiction often uses nautical

analogies to describe space travel. If the starship U.S.S. Enterprise is traveling at warp factor 1.71, what is its speed in knots?

• Warp 1.71 = 5.00 times the speed of light

• speed of light = 3.00 x 108 m/s• 1 knot = 2000 yd/h exactly

• Apothecaries (druggists) use the following set of measures in the English system:

• 20 grains ap = 1 scruple (exact)• 3 scruples = 1 dram ap (exact)• 8 dram ap = 1 oz. ap (exact)• 1 dram ap = 3.888 g• 1 oz. ap = ? oz. troy• What is the mass of 1 scruple in grams?

Examples

Examples

• The speed of light is 3.00 x 108 m/s. How far will a beam of light travel in 1.00 ns?

Temperature and Density

Temperature

• A measure of the average kinetic energy

• Different temperature scales, all are talking about the same height of mercury.

• Derive a equation for converting ºF toºC

0ºC 32ºF

0ºC = 32ºF

100ºC 212ºF

100ºC = 212ºF

0ºC 32ºF

0ºC = 32ºF

100ºC 212ºF0ºC 32ºF

100ºC = 212ºF0ºC = 32ºF

100ºC = 180ºF

100ºC 212ºF0ºC 32ºF

100ºC = 212ºF0ºC = 32ºF

100ºC = 180ºF1ºC =

(180/100)ºF1ºC = 9/5ºF

ºC

ºF

ºC

ºF

(0,32)= (C1,F1)

ºC

ºF

(0,32) = (C1,F1)

(120,212) = (C2,F2)

Density

• Ratio of mass to volume

• D = m/V

• Useful for identifying a compound

• Useful for predicting weight

• An intrinsic property- does not depend on what the material is

Density Problem• An empty container weighs 121.3 g. Filled

with carbon tetrachloride (density 1.53

g/cm3 ) the container weighs 283.2 g. What is the volume of the container?

Density Problem

• A 55.0 gal drum weighs 75.0 lbs. when empty. What will the total mass be when filled with ethanol?

density 0.789 g/cm3 1 gal = 3.78 L 1 lb = 454 g