1. Chemistry 101 Chapter 1 Goals, Method & Measurements

2. 2 Definition of Chemistry  Chemistry, is the study of that part of nature that bears on substances, their compositions and structures, and their abilities to be changed into other substances.

3. 3 Facts  Fact - a truth known by actual experience or observation. The hardness of iron, the number of ribs in a squirrel’s bodies, the existence of fossil trilobites, and the like are all facts. In science, the most reliable facts are those that can be obtained through repeated observations or measurements.

4. 4 Hypothesis  Hypothesis - a proposition explaining the occurrence of a phenomenon or phenomena, often asserted as a conjecture to guide further investigation.

5. 5 Theory  Theory - a coherent set of propositions that explain a class of phenomena, that are supported by extensive factual evidence, and that may be used for prediction of future observations.

6. 6 Famous Theories Scientists have produced lots of familiar theories:  Copernicus's theory of the heliocentric solar system  Newton's theory of gravity

7. 7 Famous Theories  Einstein's theory of relativity,  Darwin's theory of natural selection

8. 8 Facts & Theories Each of these theories draws on huge numbers of facts:  observations of the passage of the sun and planets for the heliocentric theory;  the behavior of the planets, of projectiles, and rather famously of apples for the theory of gravity,

9. 9 Facts & Theories  the existence and location of fossils, as well as the modern distribution and reproduction of organisms, for the theory of natural selection

10. 10 Properties & States of Matter  A property is any characteristic of something that can be used to identification and recognition.  Physical properties include color, height, mass, and they can be observed without the object being changed.

11. 11 Properties & States of Matter  a chemical that when observed, causes a substance to change into new substances is called a chemical property and the observation, is called a chemical reaction.

12. 12 Properties & States of Matter Physical Change  Boiling Water  Dissolving salt in water  Evaporation of water  Cooking an egg Chemical Change  Rusting of iron  Burning of wood  Cooking an egg.

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14. 14 Physical Quantities & Measurements  Length – a physical quantity that describes how far an object extends into space.

15. 15 Some Common Measures of Length SI (International System of Units) 1 Kilometer = 1000 meters 1 meter = 100 centimeters I centimeter = 10 millimeter

16. 16 Some Common Measures of Length U.S. Customary 1 mile + 5280 feet 1760 yard 1 yard = 3 feet I foot = 12 inches

17. 17 Volume  The space an object occupies Some Common Measures of Length SI 1 Cubic meter = 1000 liters 1 liter = 1000 milliliters 1 milliliter = 1000 micro liters

18. 18 Volume U.S. Customary 1 gallon = 4 liquid quarts 1 liquid quarts = 2 liquid pints 1 liquid pint = 16 liquid ounces

19. 19 Mass  Mass – the measure of the inertia of an object.  An object with a large inertia has a large mass. A large mass doesn’t always mean a large weight. This is because, mass is not dependent on location, whereas weight is.

20. 20 Mass Some common measures of Mass SI 1 kilogram = 1000 grams 1 gram = 1000 milligrams 1 milligram = 1000 micrograms 1 kilogram = 2.205ibs

21. 21 Mass U.S. Customary (avoirdupois) c 1Short ton = 2000 pounds 1 pound = 16 ounces 1 pound = 453.6 grams

22. 22 Temperature  Temperature – is the base quantity used to describe the hotness and coldness of an object.  Temperature can be expressed in :  Celsius / Centigrade  Kelvin  Fahrenheit

23. 23 Significant Figures  The number of significant figures in a physical quantity is the number of digits known with complete certainty to be accurate plus one  1.03 x 10 4 g (three significant figures) 1.030 x 10 4 g (four significant figures) 1.0300 x 10 4 g (five significant figures)

24. 24 Density & Specific Gravity  Density is the mass per unit volume of a substance (mass \ volume)  The density of substance varies with temperature, because for most substances, the mass of the substance changes with temperature, not its volume.

25. 25 Density & Specific Gravity  SubstanceDensity (g/cm 3)  Aluminum2.70  Bone1.7 – 2.0  Glass2.4 – 2.8  Gold19.3

26. 26 Density & Specific Gravity  The specific gravity of a liquid is the ratio of the mass contained in a given volume to the mass in the same unit of the identical volume of water at the same temperature.  Specific gravity is measured without units.

27. 27 The End