1. Intro to Chemistry Why Care?

2. Chemistry is Everywhere Data analysis Matter Structure of atom Elements Bonding States of matter Chemical reactions Reaction rates Thermochemistry

3. Break it Down With a MODEL –A replica or description designed to show the structure or workings of an object, system, or concept –Physical or mathematical

4. SI System –MKS system Meters, kilograms, seconds –CGS Centimeters, grams, seconds Standards of Length, Mass and Time

5. Base Units and Derived Units Base units – quantity measured from natural phenomenon Derived units – mathematically manipulated base units –Area –Volume –density

6. What is the SI base unit for length? 1.Inch 2.Kilometer 3.Meter 4.Mile 12345

7. Scientific Notation Used to obtain correct # of sig figs for really big and small numbers Check out your resources To convert large # to small #, move decimal to left To go from small to big, move decimal to right

8. How to do it on Calculator Use the EE button 5E5 means 5x10 5

9. Let ’ s Do Some Now

10. Dimensional Analysis

11. Dimension has a specific meaning – it denotes the physical nature of a quantity Dimensions are denoted with square brackets –Length [L] –Mass [M] –Time [T] But WHAT ’ S A DIMENSION? And how many are there? Dimensional Analysis

13. Conversion Factors Metric prefixes –Briefly Conversion factors –Equal to each other –2.54 cm/1 in –1 kilometer/1000 meters Use conversion factors when going from one unit to another

14. Dimensional Analysis Refers to the base quantities that make up the value –Dimension of area: Length squaredL 2 –Dimension of velocity: length/time L/T –Dimension of force: (mass)(acceleration)ML/T 2 Helps you determine if your relationships are correct

15. Unit conversion

16. Now You Practice Convert each of the following length measurements to its equivalent in meters 1.1 cm 76.2 pm 2.1 km 0.123 Mm

17. Taking measurements Take measurement to first known value and one estimated value This is the basis for the concept of significant figures (SigFig)

19. Significant Figures Rules of thumb –In multiplication, division, addition or subtraction The result should have only as many digits as the number with the least amount of significant figures used For adding and subtracting, the number of decimal places is the important consideration For multiplying and dividing, the number of significant figures is the important consideration –Keep an extra digit in calculations and then round off for the final result –Rounding If the next digit is < 5 (i.e. 0,1,2,3,4), then round down If the next digit is ≥ 5 (i.e. 5,6,7,8,9), then round up

20. Rules Zeros between other nonzero digits are significant –50.3 m (3)3.0025 s (5) Zeros in front of nonzero digits are NOT significant –0.892 m (3)0.0008 s (1) Zeros that are at the end of a number and also to the right of a decimal are significant –57.00 g (4)2.000000 kg (7) Zeros at the end of a number are not significant but to the left of the decimal are significant if they have been measured or are the first estimated digit. Otherwise they are not. –20 cm (1 or 2)

21. Calculators They don ’ t care about sigfigs

22. Accuracy and Precision

23. Thanks and Have a Great Day!