1. Unit 0 Chapters 1, 2 and 3 Mr. Crofoot - Chemistry
Units and Math
Unit 0 Chapters 1, 2 and 3 Mr. Crofoot Chemistry

2. Which of the following is not a NGSS Cross Cutting Concept?
8/20/18 Starter/Plicker
Which of the following is not a NGSS Cross Cutting Concept?
Stability and Change
Patterns
Cause and Effect
The Scientific Method /

3. 8/20/18 Write in Notebook Math Objective
Units
Math you need to know

4. 8/20/18 Write in Notebook Units
Units: the symbols at the end of a value that describes what the value represents.
The unit can have a single dimension or multiple dimensions
The unit can have a base and multiplicative prefixes
5 m
5 m/sec
500 cm/sec

5. 8/20/18 Write in Notebook Adding Values with Units
You can only add and subtract values with the same units.
If the units are same dimension but not the same unit, one can be converted to match the other before adding or subtracting.
5m + 3ft ≠ 8?
5m + (3ft x 0.305m/ft) = 6m /

6. 8/20/18 Write in Notebook Adding Values with Units Practice
Can the following values be added without a unit conversion?
10moles + 7grams (Y/N)
4miles + 6kilometer (Y/N) /

7. 8/20/18 Write in Notebook Multiplying Values with Units
You can multiply and divide values with any units. The product units are a combination (multiply and divide) of the factor units.
15 cm x 5 cm = 75 cm2
5m ÷ 3sec = 5/3 m/sec
13.5g ÷ 5.0cm3 = 2.7g/cm3 /

8. 8/20/18 Write in Notebook Multiplying Values with Units Practice
Perform the following multiplication and division with the values and the units.
20m2 x 5m = ____ ____
33m ÷ 3sec = ____ ____ /

9. 8/20/18 End of Class and Homework (Two week Sheet)
Read:
Chapter 1
Answer Mastering Concepts Question (page 22) 28
Answer Cumulative Review Questions (page 23)
5, 6, 7 /

10. Add the following values. 43.2 meters + 23.2 seconds = 66.4 meters
8/21/18 Starter/Plicker
Add the following values.
43.2 meters seconds =
66.4 meters
66.4 meter seconds
20.0 meter seconds
These values cannot be added. /

11. 8/21/18 Write in Notebook Unit Conversions
To convert a value with one unit to the value with a different unit, multiply by a ratio with the desired unit on the top and old unit on the bottom. The value represents unity between the units to convert.
5.00𝑚 × 39.4𝑖𝑛 𝑚 = 197 in
Covered in Section 2.2 of the text. /

12. 8/21/18 Write in Notebook Unit Conversions Practice
Perform the following conversions. Write the values and the units.
24𝑔 × 𝑚𝑜𝑙𝑒 12 𝑔 = ___ __
4𝑚𝐿 × 5 𝑔 𝑚𝐿 = ___ __ /

13. 8/21/18 Write in Notebook Adding Significant Figures
When adding or subtracting values with significant figures, answer should have same number of digits after the decimal as the additive value with the least digits after the decimal
5.32𝑚+ 250m = 255m /

14. 8/21/18 Write in Notebook Adding Significant Figures Practice
Add the following values and write answer with the appropriate significant figures and units.
10𝑓𝑡 ft = ____ __
3.04$+ 250$ = ____ __ /

15. 8/21/18 Write in Notebook Multiplying Significant Figures
When multiplying or dividing values with significant figures, answer should have same number of significant figures as the factor value with the least significant figures.
20.00𝑚 ÷ 5.0sec = 4.0m/sec /

16. 8/21/18 Write in Notebook Multiplying Significant Figures Practice
Multiply and divide the following values and write answer with the appropriate significant figures and units.
3.00𝑚 x 5.0𝑚 = ____ ___
16.𝑚 ÷ 4.02 sec = ____ ___ /

17. 8/21/18 End of Class and Homework (Two week Sheet)
Define the following terms:
Significant Figures
Hypothesis
Law
Fact
Independent Variable
Dependent Variable /

18. 11 meters x 39.3701 inches/meter = 433.0711 inches 430 inches
8/22/18 Starter/Plicker
Convert 11 meters to inches. What is the answer with appropriate units and significant figures?
11 meters x inches/meter =
inches
430 inches
433 inches
These values cannot be multiplied /

19. 8/22/18 Write in Notebook Scientific Notation
Instead of writing a value many digits, we can use scientific notation.
23,000,000 = 2.3 x107
Scientific notation also removes the ambiguity of the number of significant figures.
2.3 x107 Two Significant Figures
2.30 x107 Three Significant Figures /

20. 8/22/18 Write in Notebook Scientific Notation
On your calculator, scientific notation is represented by EE.
2.3EE7 = 2.3 x107
2.3EE-7 = 2.3 x10-7
EE is usually the 2nd function of a key. /

21. 8/22/18 Write in Notebook Scientific Notation
Adding/Subtracting in Scientific Notation
= 2.3 x x107
Convert one number to the Scientific Notation power of the other
= 0.23 x x107
Then add
= 2.5 x107
Note Significant Figures only to one after decimal /

22. 8/22/18 Write in Notebook Scientific Notation
Multiplying/Dividing in Scientific Notation
= (2.3 x106) x (2.30 x107)
Multiply the numbers and add the powers
= (2.3x2.30) x (106+7)
= 5.3 x1013
Note Significant Figures only two /

23. 8/22/18 Write in Notebook Scientific Notation
Practice
Subtract: (5.48 x108) - (2.3 x107) =
Divide: : (5.48 x108) / (2.3 x107)
Significant Figures? /

24. 8/22/18 End of Class and Homework (Two week Sheet)
Mastering Problems (page 51)
77 a, c, g, i
78 a, b, d, e /

25. 8/23/18 Starter/Plicker
Convert 18 meters into miles. There are 1.61 kilometers per mile. Use appropriate significant figures.
29 miles
miles
28.89 miles
0.011 miles /

26. 8/23/18 Write in Notebook Percent Error
P.E. = 𝐴𝑐𝑡𝑢𝑎𝑙 𝑉𝑎𝑙𝑢𝑒 −𝐸𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡𝑎𝑙 𝑉𝑎𝑙𝑢𝑒 𝐴𝑐𝑡𝑢𝑎𝑙 𝑉𝑎𝑙𝑢𝑒 x 100%
If a chemist determines the result of an experiment is 42.7 grams/mole, and the accepted scientific value is 43.5 grams/mole, her percent error is:
( )/43.5 x 100% = 1.84% /

27. 8/23/18 Write in Notebook What Does Math Mean?
Addition and Subtraction
A + B = C A + B = C
A - B = C A + B = C
Must have the same units to add or subtract!!!!!
Answer has the same units!!!!
When one variable is held constant, how do the other two variables change together? /

28. 8/23/18 Write in Notebook What Does Math Mean?
Multiplication and Division
A x B = C A x B = C
A ÷ B = C 𝐴 𝐵 = C
Can have any units to multiply or divide!!!!
Answer has the combined units!!!!
When one variable is held constant, how do the other two variables change together?

29. 8/23/18 Write in Notebook Solving Math Problems?
Find all the information that you are given in terms of variables and what equation to use.
Figure out what variable you are being asked to determine.
Find out what variable information is missing and locate that information.
Plug values into equation with units.
If the units do not match, then perform unit conversion.
Isolate the unknown variable. Same operation on both side of equal sign.
Solve the number problem. Does it make sense?
Solve the unit problem. Does it make sense?

30. 8/23/18 Write in Notebook Solving Math Problems?
Ideal Gas Law Example:
PV = nRT
R = (L·atm/mol·K)
P = Pressure (atm)
V = Volume (L)
T = Temperature (K)
T(K) = T(°C)x1(K/°C) + 273(K)

31. 8/23/18 End of Class and Homework (Two week Sheet)
Solve the following problems:
If the pressure is P=1.2atm, the volume is V=4.5L and the temperature is 15C, how many moles are present?
If the pressure is doubled and the number of moles and temperature are held constant, what happens to the volume, V? /

32. 8/24/18 Starter/Plicker Using the Ideal Gas Equation: P V = n R T
If the temperature (T) and number of moles (n) stay the same and the pressure (P) is increased, what happens to the volume (V)? R is a constant.
Volume increases
Volume decreases
Volume stays the same
Cannot be determined

33. 8/24/18 Write in Notebook Scientists Use the Metric System
Extensive: a property that depends on the amount of material
Intensive: a property that does not depend on the amount of material

34. 8/24/18 Write in Notebook Scientists Use the Metric System
Length Meter (m) Extensive
Volume Liter (L) Extensive
Mass Gram (g) Extensive
Time Second (sec) Intensive
Temperature Centigrade (°C) Intensive
Heat Calorie (C ) Extensive
Count 6.02x1023 (mole) Extensive

35. 8/24/18 Write in Notebook Scientists Use the Metric System
When combined with a unit these prefixes change the value by orders of magnitude.
Bigger Units
Smaller Units
Deca
or 10
Deci
or 0.1
Hecta
or 100
Centi
or 0.01
Kilo
or 1,000
Milli
or 0.001
Mega
or 1,000,000
Micro or
Gega
10+9
Nano
10-9
tera
10+12
Pico
10-12

36. 8/24/18 Write in Notebook Chemists Use the Metric System
Many of units are related by water or based on water:
One cubic centimeter (cc) is the volume as one milliliter (mL)
One cc or mL of water weighs one gram
Water freezes at 0ºC and boils at 100ºC
It takes one calorie to heat one gram (g) of water one degree Celsius (ºC).

37. 8/24/18 Write in Notebook Chemists Use the Metric System
Precision: is how well you can reproduce a measurement
Accuracy: is how close the measurement is to the real thing

38. 8/24/18 End of Class and Homework (Two week Sheet)
Review Chapter 2
Do the following Mastering Concepts and Mastering Problems (page 50-51):
61, 67, 80, 81 86 /

39. 8/27/18 Starter/Plicker
Mass and volume are both extensive properties. Density (mass/volume) is a combination of mass and volume. Density is:
Extensive
Intensive
Both Extensive and Intensive
Neither Extensive or Intensive

40. 8/27/18 Work on CRAM Sheet CRAM SHEET Unit 0
Work on CRAM Sheet today.
We will go over CRAM Sheet tomorrow.
Test on Wednesday

41. 8/28/18 Review CRAM Sheet CRAM SHEET Unit 0

42. 8/29/18 Test Unit 0 Test Unit 0