1. Matter Part 2

2. Scientific Notation

3. What is Scientific Notation?
A way to express either very large or very small numbers

4. Scientific Notation
Each number represented in scientific notation has 3 parts:
The coefficient must be greater than 1 or less than 10
The exponent can be positive or negative
Write down the 3 parts

5. Scientific Notation
Circle the numbers that are in scientific notation. 14.5x x x x x100
Ask about the zero

6. Scientific Notation

7. Converting from Standard form to Scientific Notation
Standard Form Scientific Notation
(original number is less than 1) _____________
22,598.7 (original number is greater than 10) ______________
_______________
4.7 x 10-3
x 104
5.95 x 102

8. Converting from Scientific Notation to Standard Form
A positive exponent means the number is very big
Move the decimal to the right
A negative exponent means the number is very small
Move the decimal to the left

9. Converting from Scientific Notation to Standard Form
Draw in the loops to indicate how many zeros you need to add

10. Converting from Scientific Notation to Standard Form
Scientific Notation Standard Form 3.772x104 (exponent is positive) _____________ 9.8x10-3 (exponent is negative) _____________ x106 ______________
37,720
.0098
5,360,420

11. Performing Calculations in Scientific Notation
***use the “ee” button on your calculator Example: (3.4x106)(8.792x109) = In your calculator, enter “3.4 2nd ee 6 X nd ee 9 enter” (3.4x106)(8.792x109) = 2.99x1016

12. Practice Calculations
(5.44x10-3)(6.669x108) = (1.72x1016)(3.99x10-5) = (8.116x103)

13. Precision vs. Accuracy
Precision – the closeness of a set of measurements of the same quantity made in the same way
Accuracy – the closeness of measurements to the correct or accepted value of the quantity measured

14. Percent Error
If I estimate the weight of my cat to be 10 pounds but her actual weight is pounds, what is my percent error?

15. Significant Figures

16. Sig Figs What are sig figs?
The number of figures that are shown with some degree of reliability
The number of digits used to express a measured or calculated value
Why do we use sig figs?
To show how accurate a number is

17. Rules for Significant Figures
Nonzero numbers are ALWAYS significant.
1287 g
78,483 cm
58 mL
638 mol
= 4 Sig Figs
= 5 Sig Figs
= 2 Sig Figs
= 3 Sig Figs

18. Rules for Significant Figures
Zeros in-between nonzero numbers are ALL significant.
101 mol
20,375 cd
1001 J
908 s
= 3 Sig Figs
= 5 Sig Figs
= 4 Sig Figs
= 3 Sig Figs

19. Rules for Significant Figures
Zeros after nonzero numbers (trailing zeros) WITH A DECIMAL PRESENT are significant
6.0 mg Kg
80.0 m mL
= 2 Sig Figs
= 5 Sig Figs
= 3 Sig Figs
= 4 Sig Figs

20. Rules for Significant Figures
Zeros in front of nonzero digits (preceding zeros) are not significant. They are called place holders.
0.78 Kg cd
290 amp
300 s
= 2 Sig Figs
= 3 Sig Figs
= 2 Sig Figs
= 1 Sig Figs

21. Rules for Significant Figures
Counting numbers and defined constants have an infinite number of significant figures.
1 dozen = 12
78 pencils
32 books
1 pair = 2
= Infinite Number of Sig Figs
= Infinite Number of Sig Figs
= Infinite Number of Sig Figs
= Infinite Number of Sig Figs

22. Zeros that are significant.
202 cm L
144.0 kg cd
= 3 Sig Figs
= 6 Sig Figs
= 4 Sig Figs
= 5 Sig Figs

23. Zeros that are NOT significant, PLACE HOLDERS.
= 1 Sig Figs
50 g m J
9000 L
= 2 Sig Figs
= 3 Sig Figs
= 1 Sig Figs

24. = 4 Sig Figs = 3 Sig Figs = 4 Sig Figs = 4 Sig Figs 80020 s 0.00401 kg
Zeros that are significant (called Trailing) and zeros that are not significant (call Place Holder).
= 4 Sig Figs
80020 s kg
Amp
10230 L
= 3 Sig Figs
= 4 Sig Figs
= 4 Sig Figs

25. Making Calculations with Significant Digits
Multiplying and Dividing
The final answer is rounded to have the same number of significant figures as the measurement with the least number of significant figures.
755 cm x 33 cm = 24915
92 m x 20 m = 1840
25000 cm2
2000 m2

26. 0.894 g / 2.0 g = g
40.0 x = 152
203 x =
/ =
96.0 / =
101 x = 2.02
0.45g
1.50
932000
13.0
1.25
2.0

27. Making Calculations with Significant Digits
Adding and Subtracting
The final answer is rounded so that it has the same number of digits past the decimal as the measurement with the least number of digits past the decimal
120.60
89.001
6.3 +
215.9

28. 756.05
23.02
733.03 −
733.03
9.002
2.32
45.659
56.981 +
56.98

29. 45
32.5
12.5 − 13

30. Metric System/ SI units
A universal system of measurement
Base units:
Mass: measured in grams (g)
Volume: measured in liters (L)
Length: measured in meters (m)

31. Metric Conversions Metric Prefixes Kilo (k) 1000 103 Hecto (h) 100 102
Prefix & Symbol
Numeric Multiplier
Exponent
Kilo (k)
1000
103
Hecto (h)
100
102
Deca (da) 10
101
Base/ No Prefix (m, L, g) 1
Deci (d) .1
10-1
Centi (c)
.01
10-2
Milli (m)
.001
10-3

32. Metric Conversions King Henry Died by Drinking Chocolate Milk
How many kilometers are
in 14,220 meters?
How many millimeters are
in are in 562 decimeters?

33. Metric Conversions Practice
_____________________________________________
5.6kg = ______ g daL = _____cL
75mL = ______L ,000dm = _____km
16cm = _____mm g = _____cg

34. Dimensional Analysis Convert 3.7 feet to inches.
Dimensional analysis steps:
1. Set up a picket fence.
2. Start with what you’re given in the problem.
3.7 ft

35. Dimensional Analysis Place what you’re looking for off to the side.
inches?
Choose a conversion factor.
12 inches = 1 foot
Place your conversion factor in your picket fence so your units
cancel.
3.7 ft inches
inches? ft
Solve and include the correct unit on your answer.
3.7 x 12 = 44.4 inches

36. Dimensional Analysis Practice: Convert 50 years into seconds.
How many cups are in 50mL? (1L = 4.226cups)
Convert 3.8km/s to mi/week. (1600m = 1mi)
A particular brand of gasoline has a density of 0.737g/ml. How many grams of this gasoline would fill a 12.9 gallon tank? (1gallon = 3.79 liters)
Alan is going to the Boy Scouts Jamboree in D.C. next summer and he has been asked to bring the smores supply for all the boys going from the district in Oregon. Each giant chocolate bar makes 16 smores. Each boy will be limited to exactly 3 smores. The problem is that he has to buy the chocolate once he gets to D.C. because there will be too many of them and they may melt in the summer heat. On average, the stores only carry 25 of these giant chocolate bars in stock. How many stores will he have to visit if there are 2,225 boys?

37. Density
Density is a measure of how much “stuff” is contained in a certain volume of a substance.
A low density item is “light” in comparison to something else of the same volume
Which is more dense? A or B?
Answer: A – there is more “Stuff” for the same volume! A B

38. Density Equation D = m/V D = density Units for density = g/cm3 or g/ml
M = mass Unit for mass = grams (g)
V = volume Units for volume = cm3 (if it is a solid) or mL (if it is a liquid)

39. Example Problem #1
You are given a cube made out of an unknown substance and want to find out the density.
How would you find the volume of a cube?
First you can measure one side – let’s say it is 2cm.
Volume = l x w x h
2 x 2 x 2 = 8 cm3
Then you can weigh it on a scale – let’s say its mass is 240 g
D = m/V
D = 240g/8cm3
D = 30 g/cm3

40. Example Problem #2
You are given an irregularly shaped solid made of an unknown substance and are asked to find its density.
How would you find the volume?
To find the volume you can drop it in a cylinder of water and note the change in volume – let’s say the water level rises from 22mL to 32mL.
The volume of the solid would be 10mL
Then you can weigh it on a scale – let’s say the mass is 100g
D = m/V
D = 100g/10mL
D = 10 g/mL

41. Float or Sink?
Density determines whether an object will float or sink.
If an object is less dense than the fluid it is immersed in, it will float
If it is more dense, it will sink

42. An 800 ml quantity of vanilla ice cream has a mass of 600 g
An 800 ml quantity of vanilla ice cream has a mass of 600 g. The manufacturer then bubbles air into the ice cream so that its volume increases by 400 ml. What is the ice cream’s approximate density?
0.5 g/ml
2.0 g/ml
0.75 g/ml
1.5 g/ml

43. What is the mass of a 500 ml sample of seawater with a density of 1
What is the mass of a 500 ml sample of seawater with a density of g/ml?
487.8 g
0.002 g
512.5 g
529.2

44. A block of maple wood with a volume of 405 cubic centimeters and a density of 0.67 grams/cubic centimeter is sawed in half. What is the density of the two smaller blocks?
0.335 grams/cubic centimeters
271.4 g
604.5 g/cubic centimeters
0.67 g/cubic centimeters

45. A sample of an element has a mass of 132. 6g and a density of 2
A sample of an element has a mass of 132.6g and a density of 2.55 g/ml. What is the volume in liters of the sample? L
52 L
0.02 L
0.052 L