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to Chemistry. Mr. Cowder. What is the best way to study chemistry?. An observation is information collected through the five senses. An inference is an interpretation or explanation of an observation. Observation vs. Inference. Physical Change.

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to Chemistry

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  1. to Chemistry Mr. Cowder

  2. What is the best way to study chemistry?

  3. An observation is information collected through the five senses. An inference is an interpretation or explanation of an observation. Observation vs. Inference

  4. Physical Change Physical changes occur when objects undergo a change that does not change their chemical nature. A physical change involves a change in physical properties. Physical properties can be observed without changing the type of matter. Examples of physical properties include: texture, shape, size, color, odor, volume, mass, weight, and density

  5. Chemical Change

  6. A piece of copper wire is heated in a bunsen burner causes the copper wire to change color. Physical or Chemical??

  7. Decaying Wood… Physical or Chemical??

  8. Law of Conservation of Mass In a chemical reaction, the mass of the products equals the mass of the reactants.

  9. In this chemical reaction, can you determine the reactants and the products?

  10. Distillation

  11. Page 38 Matter Mixtures Pure Substance Mercury Sodium Chloride

  12. Page 69 What is Density?

  13. The Metric System Base unit Mega kilo hecto Micro deca deci centi milli g,m,L µ c da m M k h d 106 1000 100 10 1 .1 .01 .001 10-6 Mg km hL dag dg cm mL µg = 10 grams 1000 mL = 1 L = 100 liters 100 cm = 1 m = 1,000 meters 10 dg = 1 g 1,000,000 ug = 1 g = 1,000,000 grams

  14. The factor-label method was developed to keep track of units in multi-step conversion problems. In the method, equalities (i.e., conversion factors) are set up in fraction form. The equalities are then lined up sequentially and units used on the top and bottom of neighboring fractions are alternated so that units cancel.

  15. Practice Problems: • 8.25 grams = _________kilograms? 2. 677 decagrams = __________grams? 3. 21.0 meters = ___________decimeters? 4. 4563 milligrams = _________grams? 5. 0.251 kilometers = __________centimeters? 6. 254 liters = ___________decaliters? 7. 2.9234 decigrams = __________kilograms? 8. 67.34 milliliters = ____________liters?

  16. How old are you in seconds? Remember: Use factor-label!!!

  17. Page 52

  18. The measure of how close a measurement comes to the actual or true value of whatever is measured. Accuracy

  19. Precision The measure of how close a series of measurements are to one another.

  20. Once upon a time...

  21. Page 56 Practice Problems Identify the number of significant figures: 1) 3.0800 2) 0.00418 3) 7.09 x 10¯5 4) 91,600 5) 0.003005 6) 3.200 x 109 7) 250 8) 780,000,000 9) 0.0101 10) 0.00800

  22. Percent Error Percent Error = / experiemental value – accepted value / accepted value X 100 Problem: A student in lab determines the density of mercury to be 12.2 g/ml. The actual density of mercury is 13.1 g/ml. What is the percent error in the student’s calculation?

  23. Thanks for watching!!

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