Chapter One Introduction to Chemistry What is Chemistry? Define Chemistry - • The study of the composition of matter and the changes it undergoes. Define Matter - • Anything that has mass and occupies space. What are the five branches of Chemistry? Organic Chemistry Inorganic Chemistry Analytical Chemistry Physical Chemistry Biochemistry 3.a. WHAT IS ORGANIC CHEMISTRY? STUDIES CARBON CONTAINING COMPOUNDS. • Hydrocarbons specifically 3.b. WHAT IS INORGANIC CHEMISTRY? STUDIES SUBSTANCES WITHOUT CARBON. • Mainly substances of nonliving things. 3. c. WHAT IS ANALYTICAL CHEMISTRY? CONCERNED PRIMARILY WITH IDENTIFYING UNKNOWN SUBSTANCES. • Lab based chemistry • Forensic chemistry is an example 3. d. WHAT IS PHYSICAL CHEMISTRY? SPECIALIZES IN THEORIES AND EXPERIMENTS THAT DESCRIBE THE BEHAVIOR OF CHEMICALS. • LOTS OF MATH • DESCRIPTIVE CHEMISTRY: How and why do materials behave the way they do... 3.e. WHAT IS BIOCHEMISTRY? STUDIES THE COMPOSITION OF LIVING ORGANISMS. • MEDICINES, PHOTOSYNTHESIS/RESPIRATION, CELL BIOLOGY, ETC. IS THERE CLEAR DISTINCTION BETWEEN FIELDS? NO! OBVIOUSLY THE SUBDIVISIONS OF CHEMISTRY OVERLAP. • FOR EXAMPLE, YOU CAN’T MEASURE A CHANGE IN SUBSTANCE WITHOUT SOME PROFICIENCY IN ANALYTICAL CHEMISTRY. 4. Why study chemistry? Your everyday life involves chemistry, how? a. Food Industry b. Environmental Reasons c. Medical Advances d. Better products means better lives HOW DOES CHEMISTRY AFFECT YOUR EVERYDAY LIFE? VIDEO - “CHEMISTRY IN YOUR LIFE” Directions are in the notepack. Chapter 2 (pg. 5 in Notepack) Matter and Change 2.1 Properties of matter 1. Matter – • Anything that has a mass and takes up space. 2. Mass – • The amount of matter the object contains. 3. Substance – • Matter that has uniform and constant composition. It is pure. Contains only one kind of matter. 2.1 Properties of Matter Continued 4. Physical Property – • A quality or condition of a substance that can be observed or measured without changing the substance’s composition. Write these examples in the left-hand margin Examples: Color, solubility, odor, hardness, density, melting point, boiling point. States of Matter 5. Solid – • Matter with a definite (“fixed”) shape and volume. 6. Liquid – • Matter that flows, has a fixed volume, and takes the shape of its container. 7. Gas – • Matter that takes both the shape and volume of its container. Gases are easily compressed. 8. Vapor – • A gaseous form of matter that is usually a solid or liquid at room temperature Physical Change 9. A change that alters matter without changing its composition. • Cutting, grinding, bending, boiling, freezing, melting, etc. Things to think about… Is every sample of matter a substance? • Explain Substance If a substance only defines pure matter – that is matter that is only made up of one kind of matter NOT EVERY TYPE OF MATTER IS A SUBSTANCE. In nature, we have mixtures – those forms of matter that are made up of two or more types of matter physically blended together. To review: List 5-7 physical properties of matter Answer: Color, solubility, odor, hardness, density, melting point, boiling point Which of the following are physical changes? a) b) c) d) Making caramel from sugar Carving a wooden figurine Freezing mercury Dissolving salt in water Answers: a) b) c) d) Making caramel from sugar: Chemical Carving a wooden figurine: Physical Freezing mercury: Physical Dissolving salt in water: Physical 2.2 Classifying Mixtures pg. 6 in your Note pack 1. Mixture: • Variable composition - 2 or more things put together, each retaining it’s own identity. 2. Heterogeneous Mixture > 2 or more things put together, each retains it’s own identity, but looks different throughout. > Has distinct phases 3. Homogeneous Mixture > 2 or more things put together, each retains it’s own identity, but looks uniform throughout. 4. solution • A solution is a homogeneous mixture 5. Phase Any part of a system with uniform (“same”) composition and properties. • Salt water = One Phase • Sand and Iron Filings = Two Phases 6. Distillation A process used to separate two liquids from one another based on their boiling point. How do we separate mixtures? What might be a way that we could separate a mixture of sand and salt using only physical changes? Answer: Add water to dissolve the salt. Filter the saltwater through a funnel. Boil the water out of the salt water. Left with two separate piles of sand and salt. Your turn to Practice: Are the following a Substance or a Mixture? Silver Alphabet soup Textbook Table salt (sodium chloride) Answers: Substance Alphabet soup - Mixture Textbook - Mixture Silver - Table salt (sodium chloride) - Substance Separate this mixture: What physical properties could be used to separate iron filings from salt? Answer: Iron is magnetic. Use a magnet to pull out the iron filings from the mixture. Classify the following mixtures as either Homogeneous or Heterogeneous? Spaghetti sauce with meatballs Glass Muddy water Cough syrup Mixture of nitrogen gas and helium gas Answers: Spaghetti sauce with meatballs: Glass: Hetero Homo Hetero Cough syrup: Homo Muddy water: Mixture of nitrogen gas and helium gas: Homo (gases will diffuse to blend completely) Texting 101 – this is NOT in your notes The following are shortened representations of longer phrases. What does each mean? Lol Ttyl Bff These are shorthand representations of a longer meaning. 2.3 Element and Compounds Note pack, pg. 7 Elements: • The simplest form of matter • Cannot be broken down further • Found on the periodic table • Represented by a chemical symbol –Sometimes from its English name, sometimes from its Latin name Compound 2 or more elements CHEMICALY bonded together. Still just one substance, but made of 2 or more kinds of atoms. Represented by a chemical FORMULA Symbol vs Formula Chemical symbol: • One or two letter abbreviation for the elements • Found on the periodic table Chemical formula: • Shorthand for a compound • Comprised of two or more chemical symbols • May contain subscripts to denote how many atoms of each element present in the compound. Chemical Change To turn a compound into its elements, a CHEMICAL CHANGE must occur. The elements comprising a compound have very different properties. Water Hydrogen gas + Oxygen gas Practice the Chemical Symbols Copper Oxygen Phosphorus Silver Sodium Helium Practice Naming Sn Ca S Cd P Cl K Mg Mn Practice Classifying element, compound or mixture Spaghetti sauce Glass Table sugar River water Cough syrup nitrogen 2.4 Chemical Reactions CHEMICAL REACTION – • shorthand for representing a chemical change. Reactants – Starting substances Products – Ending substances CH4 + O2 CO2 + H2O Reactants Products Chemical Reactions Heating Iron and Sulfur strongly produces a chemical change … iron sulfide is produced. see the reaction here Chemical Property The ability of a substance to undergo a chemical reaction and to form new substances. • Iron metal has the ability to rust. • Magnesium has the ability to react with acid. Law of Conservation of Mass and Energy During a chemical change, the total amount of mass and energy is a constant. The mass and energy of the reactants must equal the mass and energy of the products. Chemical Change vs Physical Change Chemical changes produces new substances. Physical changes do not produce new substances. Chemical changes can be observed by things such as color changes, • • • • heat changes (absorb heat = feel cold; release heat = feel warm), formation of a gas (bubbles) , formation of a new solid (a precipitate solid suspended in a liquid) , mass changes, etc. Practice Classify each as a chemical or physical change • • • • • • Cookies are baked Water boils Salt dissolves in water A firefly emits light Milk spoils Metal chair rusts Practice State several physical and chemical properties that could be used to distinguish between each of the following pairs of substances and mixtures • • • • Gasoline and water Copper and silver Water and salt water Aluminum and steel The Law of Conservation of Mass In any physical change or chemical change, mass is neither created nor destroyed; it is conserved. • Mass of the products must equal the mass of the original reactants Practice Law of conservation of mass. • Hydrogen and oxygen react chemically to form water. How much water would be formed if 4.8 grams of hydrogen reacted with38.4 grams of oxygen? Practice Law of conservation of mass. • Hydrogen and oxygen react chemically to form water. How much water would be formed if 4.8 grams of hydrogen reacted with38.4 grams of oxygen? Hydrogen + Oxygen Water 38.4 g + 4.8 g 43.2 g Summary On the back of our notes in the space provided, let’s draw in the classification of matter pyramid together. (page 38)