1. Warm UP (Write these down on the blank piece of paper given to you
Warm UP (Write these down on the blank piece of paper given to you. Leave some space in between each.)
UNIT 1: Measurement in Chemical Science
1. How do you measure something you can't see?
2. Why does having a standard system of measurement promote advancements in science and technology?
3. How do we know if a measurement is accurate?
4. What effects how significant a measurement is?
5. Why are units needed?
6. How are measurements used in everyday life?

2. Analyzing Data -Units -Moles -Uncertainty -Significant FIGURES
Honors Chemistry with Mr. Morgan

3. Chemistry
Chemistry is the study of matter and the changes it undergoes.
It is largely based on making measurements and analyzing data.

4. Units and Measurements
Measurements tell you 3 pieces of information. The first two are the number and the unit. Why?
EX. 10 feet.
The unit tells you what’s being measured.
The number tells you how much.
*The third piece comes a little later.*

5. Some examples of units How many types of units can we come up with?
Pounds, feet, minutes, hours, miles, seconds, rpm’s, m/h, meters/second…
There are a lot of different types of units. Can we use just any units in our measurements?

6. hhhhh
Height: about 1 fathom
Weight:15 stones
Age: 13,674,667.9 minutes
Average Salary:30,897, Russian rubles
Do you think this person will be successful in his or her search?

7. Height: 6 foot
Weight: 210 pounds
Age: 26 years
Average Salary: $1,000,000.00
Units can make the difference

8. Systeme Internationale
International System of Units. There are 7 base units in SI.
Why would everyone use a standard system of units?
Quantity
Base Units
Time
Seconds (s)
Length
Meter (m)
Mass
Kilogram (kg)
Temperature
Kelvin (K)
Amount of Substance
Mole (mol)
Electric Current
Ampere (A)
Luminous Intensity
Candela (cd)

9. Million Dollar Unit Blunder

10. Temperature Conversions
If you have Celsius and want Fahrenheit
oF= 1.8 (oC) + 32
If you have Fahrenheit and want Celsius
oC= (oF) – 32
1.8

11. Temperature Conversions
If you have Celsius and want Kelvin
K= (oC) + 273
If you have Fahrenheit and want Kelvin
YOU HAVE TO CONVERT FROM (oF) to (oC) before you can go to Kelvin. THERE IS NO DIRECT ROUTE!

12. Volume How much space something takes up.
From your math classes, how do you get the volume of a cube? What would the units be?

13. Volume
The volume of an irregularly shaped object can be found by submerging it in water, and measuring how much the water rose. What would the units be?
- Notice how the water is curved? That’s called a “meniscus”. When you see one of those, always read the measurement at eye level and at the center.

14. Density Measures how much “stuff” is in a certain amount of space.
Suit cases
40 pairs bathing shirts
of socks suit Pair Jeans

15. Density How to find density Units ? Example: Density= mass/volume
The mass of a sample of a liquid is 10 grams. Its volume is 5 ml. What’s the density?
D= 10grams/5ml
D= 2g/ml

16. Uncertainty in Data So far we know a measurement tells you 2 things
1. The number
2. The unit
The last thing is how precise the measurement is.

17. Accuracy and Precision
Accuracy: Refers to how close a measured value is to an accepted value.
If you weigh a 1 lb. bag of potatoes and the scale reads ½ a lb. then the measurement is NOT accurate.

18. Accuracy and Precision
Precision: Refers to how close a series of measurements are to one another.
If I weigh a bag of apples 5 times, and I get the weights 2 pounds, 2.1 pounds, 1.9 pounds, 2 pounds, and 2 pounds, then that scale is relatively precise.

19. A classic illustration

20. Precision in measurement
The precision in measurement is indicated by the number of digits reported. The reported digits are called SIGNIFICANT FIGURES.
This basically says that the more significant figures there are in a measurement, the better the measurement is.

21. Counting Significant Figures
Significant Figures (aka sig figs) include all known digits plus one estimated digit.
- Meter stick

22. Counting significant figures
Here’s the easiest way I know to count sig figs
THE USA METHOD
If the decimal point is Present, start counting from the Pacific side.
If the decimal point is Absent, start counting from the Atlantic side.
Start counting at the first NON-ZERO.
Once you start, don’t stop until you’re out of numbers.

23. COUNTING SIG FIGS So how many sig figs does each have? 12345 12345.
10000
10000.