1. Chapter 1 Chemical Foundations
DE Chemistry
Dr. Walker

2. Scientific Method You should be familiar with the top by now…
…maybe not so much with the bottom section.
A law summarizes what happens; a theory (model) is an attempt to explain why it happens.

3. Why Units Are Important

4. Units Of Measurement SI system, based on metric
Based on fundamental units, prefixes used to change size

5. Common Prefixes
Be familiar with the units shown in blue above

6. Uncertainties In Measurement
Notice in the measurements above that you may estimate one digit beyond the reading of the instrument.

7. Uncertainty Precision (left) – reproducibility of measurement
Accuracy (right) – Proximity to known value

8. Uncertainty Errors Random Errors (indeterminate errors)
Measurements may be high or low
Causes:
Interpretation of the uncertain digit
Procedural ineptness
Systematic Errors
Always occur in the same direction
Caused by poor measurement calibration
gun sight set too high/low
balance improperly zeroed
thermometer improperly marked

9. Sig Figs – The Return… Involve measurements The Rules… Exact Numbers
Nonzero digits….always count
Captive zeros….always count
Trailing zeros…..only count with a decimal
Leading zeros….don’t count
Exact Numbers
Not involved in measurements

10. Rules For Operations
All calculations in this course should use proper sig figs.

11. Dimensional Analysis…The Real Way!
Similar to the t-square method we used last year.
Notice the placement of the numbers and the cancelling units are exactly the same. There just isn’t a “T”

12. Dimensional Analysis…The Real Way!
Multi-step example
Three steps 1 2 3

13. Temperature Scales In science, typically Celsius or Kelvin is used
Celsius = Kelvin
Celsius = (Farenheit – 32) x 5/9
Farenheit = (Celsius x 9/5) + 32

14. Density
D = m/v
Could be in g/mL or g/cm3 for liquids (these are equivalent)
Usually in g/L for gases (molar mass/22.4 at STP)

15. Classification Of Matter
Anything that occupies space and has mass
States of Matter
Solids - rigid, fixed volume and shape
Liquids - definite volume, no specific shape
Gases - no fixed volume or shape, highly compressible
Plasma – High temperature, ionized phase of matter; found in stars

16. Mixtures Mixtures - Matter of variable composition
Heterogeneous mixtures
Having visibly distinguishable parts
Homogeneous mixtures (solutions)
Having visibly indistinguishable parts
Components of mixtures can be separated by physical means
Distillation (boiling point)
Filtration (particle size)
Chromatography (affinity for solid phase)

17. Properties Of Matter Intensive Physical Properties
Not quantity dependent
Density
Phase changes (bp, mp)
Hardness
Color
Extensive Physical Properties
Quantity Dependent
Mass
Volume
Length

18. Organization Of Matter

19. Separating Mixtures
Chromatography Distillation

20. Separating Compounds
Compounds can be decomposed to elements only through chemical changes.
2 H2O  2 H2 + O2
H2O2  H2 + O2
2 P2O5  4 P + 5 O2

21. Problem Set Zumdahl – Chapter 1
# 28, 30, 32, 38, 48, 52, 60, 64, 70, 76