1. Foundations of Chemical Computations
Dimensional Analysis
Foundations of Chemical Computations

2. What is DA?
Dimensional analysis: systematic approach to solving computations
Foundation of DA  Equalities
Equalities are used in the form of conversion factors!!

3. Equalities Common Conversions that represent equalities:
4 quarters = 1 dollar
12 in = 1 ft
5280 ft = 1 mile
They are equal across the equality.

4. Setting it up… Dimensions are shown using fractions.
The numerator and denominator of the fractions represent the equality.
Top and bottom should be equal to each other.

5. How it works In DA, you are given an initial quantity.
Using equal conversion factors, you change the units but NOT THE AMOUNT.

6. Examples Ex. 1: Time 2.4 hours = ______ minutes Ex. 2: Time
1 year = ______ seconds

7. Turtle Island Activity
Answer the following question using DA and the manipulatives.
A group of scientists went to turtle island with 375 research questions. How many turtles actually exist on turtle island?

8. * (top1 x top2 x top3….)/(bottom1 x bottom2 x bottom 3) =
DA WS 1
Fake Units WS
Hints:
*If your given and unknown can be found in the same equality, it is ONE STEP.
* (top1 x top2 x top3….)/(bottom1 x bottom2 x bottom 3) =

9. Making it Metric
Dimensional Analysis will first be utilized in CHEM for unit conversions.
Based off of the metric system.
Metric system has a unique set of prefixes
Prefixes will be used with any and all SI Base Units

10. What you need to know…
You must memorize the prefixes, abbreviations and ‘values’.
You must be able to make equalities

11. EQUALITIES
The most simple equalities will always be connected to the base unit.
___ dm = ___ m
___ g = ___ kg
___ TL = ___ L

12. Metric Prefixes T G M k h da d c m n p 12 9 6 3 2 1

13. Trick to Remember? Tall Gorillas May karry heavy desks Base
dogs can meet many new people

14. EQUALITIES
**Easiest way is to give the larger [furthest to the left] prefix a number 1, then provide the smaller unit with the ‘value’**

15. Examples
Convert: 415 nm = _________ m
Convert: 100 kg = ________ g

16. Hints!
Base to prefix prefix to base = 1 dimension Prefix prefix = 2 dimensions

17. Examples Ex. Convert: 14 Mg = _______ mg
Convert: 3.45 cm = _________ km

18. Other Equalities to know:
1 in = 2.54 cm
1 hour = 3600 s
1 mile = 5280 ft
1 kg = 2.2 pounds
1 cm3 = 1 mL

19. Practice
Convert:
10 cm = ____ m
5.5 m = ____ mm

20. Practice
Convert:
0.001 kL = _____ cm3
675 nm = ____ km