Créer une présentation
Télécharger la présentation

Télécharger la présentation
## Structure Determines Properties

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**Chemistry: the field of study concerned with the**characteristics, composition, and transformations of matter • Matter: anything that has mass and occupies space • Living and non-living • Macroscopic and microscopic**Structure Determines Properties**• Everything is made of tiny pieces called atoms and molecules. • Chemists believe that the properties of a substance are determined by the kinds, numbers, and relationships between these pieces.**The Scientific Method**• A process for trying to understand nature by observing nature and the way it behaves, and by conducting experiments to test our ideas. • Key characteristics of the scientific method include Observation, formulation of Hypotheses, Experimentation, and formulation of Laws and Theories.**Qualitative**Data obtained from one’s opinion Does not involve numbers Quantitative Data obtained from measurements Involves numbers Data**U.S. Customary System**• Also called: • American System • English System • Inch • Gallon • Pound • Teaspoon**Metric System**• Système International (SI) • International decimalized system of measurement • First adopted by France in 1791 • Meter • Gram • Liter**Length**• How long something is… • SI unit = meter (m)**Mass**• Measure of the quantity of matter (stuff) in an object • SI unit = Kilogram (kg)**Volume**• The amount of space that an object or substance occupies. • SI unit = Cubic meter (m3) • 1 L = 0.001 m3 • 1 L = 1000 mL • 1 mL = 1 cm3 = 1 cc**Time**• Duration of event • SI unit = Second (s)**1. Dimensional Analysis**• Using units as a guide to problem solving is called dimensional analysis • Figure out which unit you want to start with and which one you want to get to • Use conversion factors to get there • Relationship between two units • May be exact or measured • Generated from equivalence statements • Always include units in your calculations!**Problems**• Green light has a wavelength of approximately 550 nm. What is this value in meters? Picometers? Kilometers?**Your neighbor lost 50 pounds. How many kg did she lose? How**many micrograms? • How many milliseconds in a year?**Temperature**• A measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units or degrees designated on a standard scale. • A physical property that determines the direction of heat flow in an object upon contact with another object. • Fahrenheit(°F),Celsius (°C),Kelvin(K)**ºF = ºC(1.8) + 32**ºC = (ºF – 32)/1.8 K = ºC + 273 ºC = K – 273 Fahrenheit (ºF), Celsius (ºC), Kelvin (K)**Problems Using Equations: temperature, density, molarity,**ideal gas law, etc. • You are feeling sick and decide to take your temperature. Your thermometer, which only reads temps in Kelvin, says that you are at approximately 312 K. Do you have a fever?**Density = m/V (mass/volume)**A ring has a mass of 5.84 g and a volume of 0.556 ml. What is it’s density? If the density of platinum is 21.4 g/ml, is the ring made of platinum?**Percentages: set up a ratio (usually the smaller number over**the larger number) X 100 to get the %. If there were 40 questions on your test and you got 28 correct, what was your grade as a percentage?