1. What is Chemistry? Chapter 1

2. Scientific Method Observations Hypothesis Experiment Results Revise (if necessary) Conclusions

3. The Method in Action Science is a methodology It is systematic and objective. The goal of all science is to understand – To codify the laws of nature = What? And to construct models of how nature works (to explain it) = How/Why? Go here: http://bit.ly/NlpTWV

4. Law Theory Prediction Experiment Theory modified Extending the Method Experiment Observations Hypothesis

5. It’s Just a Theory… Theory – A model that provides an overall explanation that agrees with observed behaviors. e.g. Newton’s Theory of Gravity Scientific Law – A summary of observed (measureable) behavior. e.g. Newton’s 1 st Law of Motion When a model is labeled a theory, in science, it is as close to being proven as humanly possible.

6. What is Chemistry? The study of Matter. Specifically, it is the study of Chemicals, Their properties and behaviors, And the changes they undergo.

7. What is a Chemical? A substance that has a definite Composition (it’s always the same). For example, Water is H 2 O It’s the same here in Moorestown as it is in California – still the same stuff on Mars

8. In The Beginning… The universe can be divided up into two categories: matter and energy. Matter is defined as anything that has mass and takes up space. Matter is the stuff we think of when we think of stuff. Energy is most easily described as light and heat, though the formal definition is: “The capacity to do work.”

9. What is Mass? Mass is a fundamental property. It is a measure of the amount of matter in an object. It is measured in kilograms (kg) or grams (g). 453.59 grams are in 1 pound (mass). 2.2046 pounds (mass) are in 1 kilogram.

10. What is Volume? Volume is a measure of the size of an object or region in 3-D space. Volume has cubic units – basically l*w*h. It is typically measured in liters (L). 1,000 cubic centimeters (cm 3 ) = 1 Liter That’s equivalent to a cube 10 cm per side. There are 3.785 liters in 1 gallon.

11. Mass & Weight Weight is a measure of the gravitational force exerted on an object. It is measured in Newtons (N). There are 4.448 Newtons in 1 pound (force). On the surface of the Earth, 1 pound (mass) is equal to 1 pound (force).

12. Properties of Matter Matter can be identified by its properties. There are two main types: #1 Intensive Properties are those that do not change. They are always the same, regardless of the amount of substance present. They are also called Characteristic properties because they can be used to identify the substance.

13. Common intensive Properties Boiling & freezing points, Density Color Hardness Crystal structure Conductivity, & Reactivity.

14. Extensive Properties #2 Extensive Properties depend on the amount of substance present. They vary from sample to sample and cannot be used to identify substances. Common Extensive Properties are: length, mass, weight, & volume.

15. Characterization Many Intensive properties are qualitative. Qualitative properties are characteristics that cannot be measured. When qualitative properties are noted, the quality of the substance is described. Some examples are color, luster, reactivity, & conductivity.

16. Characterization w/ Numbers Extensive & some Intensive properties are quantitative. Quantitative properties are characteristics that have to be measured. When quantitative properties are noted, the quantity of the substance is described. All quantitative properties must have a number and a unit. Numbers without units are meaningless. ALWAYS REMEMBER THE UNITS!!!

17. Quantitatively Speaking Some quantitative properties are measured directly using some tool. They are called direct measurements and carry the units of the tool. For example, measuring the length of a piece of steel with a ruler will give you a quantitative property, length, with centimeters (or inches) as the unit.

18. Indirection Some characteristics cannot be measured directly. They must be calculated from other direct measurements. Properties like this are called derived measurements. Derived measurements include the units of each measurement used to derive them.

19. Derived Properties For example, the volume of a cube must be calculated. If a side of a cube measures 4 cm, then the volume is: 4 x 4 x 4 = 64 cm x cm x cm = cm 3 volume = 64 cm 3

20. Another One Speed is another derived quantitative property. It is calculated using distance traveled per unit of time. (s = d ÷ t) For example, if a ball rolls 24 meters in 5 seconds, its speed is 24 m ÷ 5 s: 24 / 5 = 4.8 m ÷ s = m/s Speed = 4.8 m/s

21. Intensive from Extensive Some intensive properties can be derived from extensive properties. Density is a quantitative intensive property that is derived from two quantitative extensive properties: mass and volume. But more on that later…

22. PropertyValueIntensive/ExtensiveQuant/QualDirect/Derived 1 Length8.76 cm 2 ColorPurple 3 Weight3.2 kg 4 Density1.02 g/mL 5 Pressure14.7 psi 6 Temperature98.6°F 7 LusterMetallic/Shiny 8 Melting Point16.2°C 9 Force48.1 kgm/s 2 10 ColorGreen (532 nm) 11 Speed758 m/s 12 ReactivityReacts w/ Water 13 Volume143.2 mL 14 Crystal TypeFace-centered

23. PropertyValueIntensive/ExtensiveQuant/QualDirect/Derived 1 Length8.76 cmExtensiveQuantitativeDirect 2 ColorPurpleIntensiveQualitativen/a 3 Weight3.2 kgExtensiveQuantitativeDirect 4 Density1.02 g/mLIntensiveQuantitativeDerived 5 Pressure14.7 psiExtensiveQuantitativeDerived 6 Temperature98.6°FExtensiveQuantitativeDirect 7 LusterMetallic/ShinyIntensiveQualitativen/a 8 Melting Point16.2°CIntensiveQuantitativeDirect 9 Force48.1 kgm/s 2 ExtensiveQuantitativeDerived 10 ColorGreen (532 nm)IntensiveQuantitativeDirect 11 Speed758 m/sExtensiveQuantitativeDerived 12 ReactivityReacts w/ WaterIntensiveQualitativen/a 13 Volume143.2 mLExtensiveQuantitativeDirect or Derived 14 Crystal TypeFace-centeredIntensiveQualitativen/a