Chemistry (Ch. 1) The study of Composition of Matter and the changes it undergoes.

Branches of Chemistry 1. Organic (Carbon containing) -Largest branch - e.g., Gasoline, plastics, fossil fuels… 2.Inorganic (No Carbon) - e.g., Mining and refining metals. 3.Biochemistry (Living organisms) - e.g., Photosynthesis, Life cycles and processes. 4.Analytical (Composition) - e.g., Breaking down molecules... 5.Physical Chemistry (Behavior) - Theory of chemical behavior - Relies on Math and Physics

Pure Science vs. Technology 1. Pure Science -Want to learn for the sake of increasing knowledge 2.Technology (Applied Science) - Make something useful in society - (Risks and Benefits)

Types of Measurements 1. Qualitative (qualities like color, shape…) - Contains no numbers e.g., The explosion was loud 2. Quantitative (Amounts) -Contains numbers e.g., The explosion was 250 decibels

Nature of Measurement Part 1 - number Part 2 - scale (unit) Examples: 20 grams 6.63 x Joule seconds Measurement - quantitative observation consisting of 2 parts

What can Chemistry show us?

Photosynthesis Equation (Biochemistry) (CARBON CYCLE) Plants use sunlight energy to make molecules Carbon dioxide + water + sunlight  Glucose + oxygen CO 2(g) +H 2 O (l) + energy  C 6 H 12 O 6(s) + O 2(g) We convert plants back into energy Sugar + oxygen  carbon dioxide + water + energy C 6 H 12 O 6(s) + O 2(g)  CO 2(g) + H 2 O (l) + energy

What are your sources of energy?

Electricity from: Nuclear, Coal, or Batteries Heating and Transportation from: Fossil Fuels (Coal, Natural Gas, Petroleum) Gasoline (mixture of petroleum molecules) Wood Personal energy to move and keep warm: Food

Batteries (Inorganic Chemistry) Electricity from studying nature: Voltaic Pile (electric eels) From studying chemistry of elements: Wet Cell (Car battery) Dry Cell (Flashlight battery) Alkaline battery (Energizer, Duracell,…) Nickel-Cadmium (Rechargeable) Lithium-Iodine/ Lithium metal hydride (Cell phones, I-pods, MP3s,…)

Risks of Technology Air Composition: »78% Nitrogen »21% Oxygen »0.9% Argon »<0.01% Helium, Neon, Carbon dioxide, Water vapor, pollutants Increases in carbon dioxide and pollutants cause Global Climate Change in the form of… »Acid Rain (Gases mix with water vapor to make acid) »Greenhouse Effect (Trapped heat energy) »Ozone depletion (Hole in ozone causing skin cancer from radiation from space)

Acid Rain Gases like CO 2 can react with water vapor in the air to make acid rain. Word Equation Carbon dioxide + Water  Carbonic acid Chemical Equation CO 2 (g) +  H 2 CO 3 (aq) H 2 O (g) (a weak acid) George Washington: BEFORE George Washington: AFTER Effects of Acid Rain on Marble (calcium carbonate)

Basic definition: Acids:Produce hydrogen ions, H +, when dissolved in water. Bases:Produce hydroxide ions, OH -, when dissolved in water.

Acid-Base Neutralization Acid+ Base  Water+Salt HCl+ NaOH  +NaClH2OH2O H+H+ OH -

Acids Have a pH less than 7 Rain water is acidic

Acid Rain Gases like CO 2 can react with water vapor in the air to make acid rain. Carbon dioxide + Water  Carbonic acid CO 2 (g) +  H 2 CO 3 (aq) H 2 O (g) Additional gases that make acid rain: (strong acids) SO 2 (g) NO 2 (g) +  H 2 SO 4 (aq) H 2 O (g) +  HNO 3 (aq) H 2 O (g) (a weak acid) Note: these equations are not balanced From burning coal From vehicle emissions Sulfuric acid (used in car batteries) Nitric acid

Greenhouse Effect Gases like CO 2, methane, CH 4, water vapor, H 2 O, and sulfur dioxide, SO 2, can prevent energy from the sun from escaping into space. This trapped heat can cause the air molecule to warm up. Surface of the planet CO 2 CH 4 H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O CO 2 SO 2 CH 4 CO 2 SO 2 H2OH2O

Ozone Depletion Ozone is a toxic gas and a three-atom (triatomic) oxygen molecule: Formula = O 3 (g) It is produced by any electrical discharge. The ozone layer in our upper atmosphere blocks harmful gamma radiation protecting us from cancer forming radiation. Surface of the planet O3O3 O3O3 O3O3 O3O3 O3O3 O3O3 O3O3 O3O3 O3O3 O2O2 O3O3 O2O2 O2O2 O3O3 O3O3 O3O3 O3O3 O3O3 Cl 2 F2F2 F2F2 F2F2 CFCCFC CFCCFC CFCCFC CFCCFC CloroFluoroCarbons, CFC’s, from air conditioner and refrigerators are reacting and destroying the ozone layer

Steps in the Scientific Method 1.Observe Nature (Observations) - qualitative (No numbers) e.g., The explosion was loud. -quantitative (Numbers) e.g., The explosion was 250 decibels. Find Order (Search for scientific laws) Formulating hypotheses - possible explanation for the observation that can be tested with an experiment. Performing experiments (Repeat 1-4) - gathering new information to decide whether the hypothesis is valid Theory  Explain and predict (Modify as new evidence arises)

Outcomes Over the Long-Term Theory (Model) - A set of tested hypotheses that give an overall explanation of some natural phenomenon. Natural Law - The same observation applies to many different systems - Example - Law of Conservation of Mass Laws describe patterns in nature. Theories explain the laws of nature but… CAN be replace with a new theory based on… Better understanding or… Improvements in experiments.

Law vs. Theory A law summarizes what happens A theory (model) is an attempt to explain why it happens.

Controlled Experiment Control: Changing ONE variable at a time to determine how it affects the outcome.