1. Chemistry

2. What is Chemistry
~The science that deals with the materials of the universe and the changes these materials undergo.
The study of the interactions of matter (atoms and molecules) and the energy involved

3. Gathering Information
Observation- a fact you use one of your five senses to determine
(the thermometer reads 24o C, this font is white)
Inference- something you reason out
(Heat entered the liquid causing the temperature to rise)
Inferences are not as reliable as observations but sometimes required.

4. Problem Solving 1. Recognize some problem, and clearly state it.
2. Propose a possible solution to the problem, this is formulating a hypothesis.
3. Test your hypothesis by running some type of an experiment

5. Scientific Method ~A procedure for solving problems Observation
Gather information
Form a hypothesis
Test your hypothesis
Analyze your results
Draw conclusion or restate hypothesis
Repeat your work
Publish or share it with others

6. It is not an exact sequence
Repeat your work
And share it with others
Gather info
Draw conclusion
Form hypothesis
Problem
Analyze results
Test hypothesis

7. Experiment There are many ways to experiment
Variable- what you are testing
only test one variable at a time
A control group is necessary for an accurate comparison (the experiment without the variable)
Blinded control groups don’t know they are the control
Double blinded studies have patients who don’t know they are the control and experimenters who don’t know they are working with the control

8. Theories and Laws Common definitions of these words cause confusion.
Theory- common definition is a hypothesis. An educated guess as to the solution of the problem.
Law- a rule, that must be followed.
THIS IS NOT THE DEFINITION OF SCIENTIFIC THEORY OR LAW!!

9. Theories and Laws
Theory- attempts to explain why data gained from conclusions and observations are so.
Law- summary of what is said in several conclusions and observations.
Theories do NOT become laws!
The names have nothing to do with level of acceptance.

10. Models Model- any representation of an object or a system
A theory is sometimes called a model as it explains helps to explain how something works.
The theory or model of how a gas works would be countless tiny particles (atoms and molecules) moving about rapidly colliding with everything.
This is the best possible accepted account for why gas act the way they do.

11. Laws A Natural Law is a summary statement.
Like Charles’ Law, put simply, heating a gas makes it expand, cooling it makes it contract.
There is no why in a Law, just what happens.
A law is NOT a more proven version of a theory, it is a different type of a statement.

12. Lab Safety

13. In the event of an accident…
REMAIN CALM!!!!!!
Get someone who knows what to do.
Don’t do anything “helpful” unless
you are asked
someone is in serious danger

14. Appropriate Dress Goggles Closed shoes—No Flip flops or sandals.
Long hair must be tied back.
Nothing dangling loosely from you.

15. Lab Safety Equipment Fire extinguisher Fire Blanket Shower Eye Wash
If there is a large fire on equipment or the room
If a person is on fire
If a chemical is spilled on someone’s body (everyone but the victim will leave the room)
If a chemical is in someone’s eyes

16. Other equipment First Aid kit Broom and dustpan broken glass bucket
Chemical Spill Clean up kit
Gas turn off button
Fire alarm
for minor injuries
for broken glass or metal
all sharp objects go in here
For chemical spills
Turns off all gas to room
in case of emergency pull

17. The Metric System
and conversions

18. Why use the metric system?
is it just to annoy American high school science students?
It is used by (almost) the entire world except for the United States. (Myanmar and Liberia are the only other hold outs)
Easy to replicate.
Easier to convert between units.

19. The “SI” system
SI is a subset of the metric system. SI stands for Systeme
Internationale d’Unites or the International System of Units.
length
meter m
mass
kilogram Kg
volume
liter L
temperature
Kelvin/ Celsius
K / C
amount of substance
mole
mol

20. Metric Prefixes Name Symbol Meaning Tera T Giga- G Mega- M 1,000,000
1,000,000,000,000
Giga- G
1,000,000,000
Mega- M
1,000,000
Kilo- k
1,000
Hecto- h
100
Deka- da 10
(base)
Deci d
1/10
Centi- c
1/100
Milli- m
1/1,000

21. Converting between Units (Dimensional Analysis, Factor Label Method)
to convert one unit to another you need conversion factors.
Conversion factor- how much of one unit equals another unit
Ex. 1 kg = 2.2 lb or 1000 m = 1 km
Therefore 1 kg/ 2.2 lb = 1 or 2.2 lb / 1 kg =1
you can always multiply any number by one and not change the number

22. Write down your given and underline it.
draw an H or a field goal post next to it.
in any H or field goal post you can put one conversion factor (half on top half on bottom).
put the unit you want to cancel out on the opposite side of the field goal.
multiply by everything on top, divide by everything on the bottom.
Convert 52 lbs to kg. (2.2 lbs = 1 kg)
1 kg
52 lbs
= 23.6 kg
2.2 lbs
lbs divided by lbs cancel out

23. 1 yd = .9144 m How many meters are in a football field (100 yds)?
100 yds yds
1yd
.9144 m
=91.4 m
.9144m
1 yd
no, the units you want to
cancel have to be on the
opposite side.
yards divided by yards
cancel out
You can always do more than one step with this method.
How many meters is 100 ft? (1yd = 3ft)
100 ft
1 yd
.9144 m
= 30.5 m
3 ft
1 yds
feet and yards cancel
but you have to go to meters so…

24. 1 kg = 2. 2 lb, 1000g = 1 kg 1000 mL = 1 L 30 mL = 1 fl oz, 3
1 kg = 2.2 lb, 1000g = 1 kg 1000 mL = 1 L 30 mL = 1 fl oz, 3.8 L = 1 gal
How many kg are in 175 lbs?
175 lbs
1 kg
2.2 lbs
= 79.5 kg
how many grams are in 175 lbs?
=79,500 g
175 lbs
1 kg
1000 g
2.2 lbs
The key to doing multi-step problems is figuring out a
“plan of attack”
in the last problem I can convert
lbs kgg, then fill in your H’s to match
How many fl oz are in .32 gal? (you will need 3 H’s)
0.32 gal
3.8 L
1000 mL
1 fl oz
1 gal
1 L
30 mL
=40.5 fl oz

25. If you have a unit expressed as a fraction..
put the number and the numerator as the given, and write
the denominator below the line, then proceed with the rest
of the rules
convert 250 g/L to g/mL
250 g L
1 L
=.25 g/mL
1000 mL
liters cancel
Convert 42 km/hr to m/s
1 min
42 km
1 hr
1 hr
=11.7 m/s
60 min
60 s

26. Sig Figs
Significant Figures

27. What are Sig Figs?
I read on the Forbes list that Jimmy Haslam (owner of the Browns) has a net worth 1.8 billion dollars.
Myself and a friend bought 4 tickets for $264.30
Assume that immediately after it was reported, I ran to Mr. Haslam with cash. Jimmy gets every penny and hasn’t had another expense yet. Does that mean Jimmy Haslam now has exactly $1,800,000,264.30?
Of course not, all of those 0’s were actually numbers that we didn’t report because we didn’t measure accurately enough.
The number was rounded!

28. This is where sig figs come into play
Absolutely accurate measurements are impossible!!!
We must round somewhere
When we do calculations with these numbers we must reflect how accurate our initial numbers were.
Significant digits means that digit was accurately measured
Insignificant digit means that digit was NOT accurately measured.

29. Rules for determining if a digit is significant
If it is not a zero, it is significant.123
If a zero is between two significant digits, it is significant. 309
Zeros at the end of a number with a decimal point are significant
Zeros at the end of a number that do not have a decimal point are NOT significant
Zeros at the front of a decimal are NOT significant

30. Determine how many sig figs are in each number
734
100,025
.00034
527.00
16.01

31. Round each number to the given number of sig figs
(2) 734
(4)
(3)
(5)
(4)
(3)
(5) 16.01
(3) 18700

32. When adding or subtracting.
How to report answers
When multiplying or dividing.
You can only have as many sig figs in your answer as you do in the number with the least amount of sig figs.
3.56 x 2.1=
7.476
7.5 (2 sig figs)
When adding or subtracting.
Numbers added to or subtracted from insignificant numbers are insignificant (rounded off).
368.58
369
insignificant

33. Examples
1.24 x 34
983200/ 124
772000
+ 5710
323400

34. Exemptions from sig figs
some numbers have an infinite number of sig figs. Meaning we can ignore them in our calculations
If a something = 1(unit), that one has an infinite number of sig figs. 1 yd = m
many conversion factors have an infinite number of sig figs, for example 3 ft = 1 yd, 60 sec= 1 min, 100 cm = 1m.
Not all conversion factors have an infinite number of sig figs though.
.9144 m = 1 yd, 2.2 lbs = 1 kg.
If you are ever unsure, ask me!

35. Important Rule Only use sig figs in your answer.
Do NOT round in the middle of the problem!!!

36. Problem 1 yd = .9144 m 3 ft = 1 yd, 60 sec= 1 min, 100 cm = 1m.
Convert 79 ft to yards to the correct number of significant figures.

37. Another
A 17.5 g object is placed in a graduated cylinder. The volume of the water in the graduated cylinder rises from 12.5 mL to 23.5 mL. What is the density of the object to the correct number of significant figures?

38. Scientific Notation
some numbers so large or small that is a pain to write out normally
for example Jimmy Haslam has $1,800,000,000
To write in scientific notation write down all sig figs x10x
The number is always written to the ones place with a decimal
so the above number is $1.8x109

39. Quick conversions 6.7 x10-7 2.31 x105 5.79 x103 4.19 x10-5 .0065
94,100,000
9,840

40. Scientific notation has to be used to correctly write some answers
For example
1329 / 13
= rounded to 2 sig figs would be…
You Have To Write This Number In Scientific Notation!
1.0x102

41. scientific notation and your calculator
To put numbers in scientific notation in your calculator there is normally an E or EE or EXP key
That E EE or EXP replaces the x10
Pay attention to the way your calculator denotes scientific notation!!!

42. Temperature Conversions
The United States is the only country to measure temperature in Fahrenheit.
Most countries measure temperature in degrees Celsius.
A conversion needs to be made
Tc = (TF-32)(.56)
TF = Tc(1.8) + 32
Kelvin is the SI unit of measure for temperature but is only used in extreme heat or cold situations
K = Tc + 273
Tc = K - 273