CRHS Academic Chemistry Unit 1 Matter and Change Notes

Transcription

1 Name Period CRHS Academic Chemistry Unit 1 Matter and Change Notes Key Dates Quiz Date Exam Date Lab Dates Notes, Homework, Exam Reviews and Their KEYS located on CRHS Academic Chemistry Website:

2 Page 2 of 12 Unit 1 Notes 1.1 MATTER Definition - Matter is anything that has MASS and takes up SPACE Chemistry is the science that describes matter, how it changes, and how those changes affect energy. To start, how do we classify matter? By their states (or phases)! THE STATES (or phases) OF MATTER Shape? Volume? Particle Arrangement? Tightly packed particles (moving!) Effect of change in pressure? No change Solid Definite Shape Definite Volume Liquid NO Definite Shape Definite Volume (takes shape of container) Closely packed, but particles glide over one another. Very Little change Gas NO Definite Shape NO Definite Volume (fills container) Loosely arranged particles travel randomly through the container. Significant amount of change OK, but WHAT is matter? ALL matter is composed of of chemical elements An atom is one type of particle in chemistry, and is the smallest unit of an element. Mass is the amount of the object contains. Regardless of state, ALL MATTER can be divided into groups: P S and M

3 Unit 1 Notes Page 3 of Pure Substances have a constant composition throughout the sample; contain only ONE type of matter. o Element the form of matter and are made of only type of atom. The PERIODIC TABLE lists all known elements. Flerovium (114) and Livermorium (116) were added in Division of the parts of an element is called a nuclear reaction, a topic for another day. o Compound or more elements bound together. Can be divided into simpler substances only by a chemical reaction (Example: MgCO3 decomposes into MgO and CO2) Mg - CO2-2. Mixtures a physical blend of substances. Contains more than one type of matter; composition may vary. Can almost always be separated by physical means. Iced tea, ocean water, sand, and steel are examples. o Homogeneous appears (uniform) throughout. A homogenous mixture containing a liquid is called a solution (Ex. Salted water) o Heterogeneous DO NOT appear uniform. We can easily see different parts of the mixture. (Ex. )

4 Page 4 of 12 Unit 1 Notes MATTER Pure Substances Mixtures Chemical vs. Physical Properties A Property is a CHARACTERISTIC of a pure substance. They can either be physical or chemical. 1. Physical property can be observed or measured BUT DOES NOT CHANGE the identity of a material. a. property depends on the AMOUNT of matter present (mass, length, heat, volume) b. property does NOT depend on the amount of matter present (density, specific heat, melting point, phase) EXTENSIVE Depends on AMOUNT of matter Mass Volume Length INTENSIVE Does NOT depend on amount of matter Density Color Melting Point

5 Practice: Label property as Intensive (I) or Extensive (E) Blue Color Mass Volume Temperature Boiling Point Hardness Density Unit 1 Notes Page 5 of Chemical property ability of a substance to undergo a change that changes the identity of the substance. Examples: *Turn to pages 11 to look for properties of hydrochloric acid (HCl) in the Material Safety Data Sheet. MSDS are available for all chemicals in the lab both in our MSDS binder AND online!

6 Page 6 of 12 Unit 1 Notes 1.2 DENSITY Density is an intensive property of pure substances that is a ratio of the mass of an object relative to the volume of the same object. Density = Mass Volume d = m v Units: MASS is measured in metric unit grams (g) VOLUME is based in either: i. milliliters (ml) ii. cubic centimeters (cm 3 ) 1 ml = 1 cm 3 Density will be expressed in g/ml OR g/cm 3 Example: What is the density of a 114 g mass of lead that has a volume of 10.0 cm 3? d = m v The density of water at room temperature is 1.00 g/cm 3. Therefore Anything with a density than 1.00 g/cm 3 will sink in water (Density > water) Anything with a density than 1.00 g/cm 3 will float in water (Density < water) Example: A cube of ice has a mass of 5 g and a volume of 10 cm 3. Will this ice cube float in a glass of water? d = m v

7 Unit 1 Notes Page 7 of 12 Practice: You have a 23.0-g sample of ethanol with a density of g/ml. What volume of ethanol do you have? Practice: The density of aluminum is 2.7 g/ml. How much mass is there in a 3.0 ml sample of aluminum? Practice: A piece of metal with a mass of 147 g is placed in a graduated cylinder. The water level rises from 20.0 ml to 41.0 ml. What is the density of the metal?

8 Page 8 of 12 Unit 1 Notes 1.3 PHYSICAL vs CHEMICAL CHANGE & CONSERVATION OF MASS Physical change alters a material without changing its identity. Examples: change (melting, freezing, sublimating, evaporating, condensing), cutting, breaking, separating, dissolving Phase Change Diagram (Physical Change) Temperat ure Boili Melt Thermal Energy Chemical change any change in which pure substances are converted into different pure substances with different characteristic properties. A chemical change means a chemical reaction has occurred. Examples: Chemical reactions are accurate and balanced representations of the events of chemical change. We write them like this: REACTANT(S) PRODUCT(S) Reactants Substances that begin a chemical reaction; written on the LEFT side of the arrow Products Substances produced by a chemical reaction; written on the RIGHT side of the arrow

9 Unit 1 Notes Page 9 of 12 Examples of Chemical Reactions (We study the types of chemical reactions in Unit 8) 2H2 + O2 2H2O 2NaCl 2Na + Cl2 2 Li + MgBr2 Mg + 2 LiBr FOUR Indicators of a chemical change/reaction 1. exchange (temperature change, emission of light) 2. Change in 3. Production of (odor, bubbles) 4. Formation of a precipitate Precipitate: an insoluble product of a chemical reaction. Usually a solid. Practice: Label the examples below as physical or chemical changes. a. Iron rusting b. Glass breaking c. Rubbing alcohol catches fire d. Polar ice cap melts e. Glucose dissolving in water f. Bathroom cleaner on lime scale creates small bubbles and the lime scale breaks down

10 Page 10 of 12 Unit 1 Notes Law of the Conservation of Mass Law of Conservation of Mass in words Matter cannot be created or destroyed Law of Conservation of Mass as a formula In a chemical reaction, the mass of the reactants the mass of the products. Example: Consider the chemical reaction in which carbon reacts with oxygen to produce carbon dioxide. What mass of carbon dioxide would be produced if 20.1 grams of carbon reacted completely with 62.5 grams of oxygen? C + O2 CO g 62.5 g? The Conservation of Mass law tells us that the total mass on both sides must be equal, so 20.1 g g = 82.6 g Practice: When ammonium nitrate (NH4NO3) breaks down explosively, it forms nitrogen gas (N2), oxygen gas (O2), and water(h2o). When 38 grams of ammonium nitrate explode, 13 grams of nitrogen and 7 grams of oxygen are formed. How many grams of water are formed? NH4NO3 N2 + O2 + H2O Practice: Methane (natural gas) is reacted with oxygen in residential furnaces to generate heat during colder months. The same reaction is used in our laboratory as a common heat source. It takes 500 g of oxygen to burn 125g of methane completely generating 281 g of water. What mass of carbon dioxide was also generated? CH4 + 2O2 CO2 + 2H2O + Heat

11 Material Safety Data Sheet (MSDS) SECTION 1 CHEMICAL PRODUCT / COMPANY IDENTIFICATION Hydrochloric Acid Flinn Scientific, Inc. P.O. Box 219 Batavia, IL (800) SECTION 2 COMPOSITION, INFORMATION ON INGREDIENTS Hydrochloric acid ( ) Synonyms: muriatic acid, toilet bowl cleaners, tile cleaners CAS# - None established Unit 1 Notes Page 11 of 12 SECTION 3 HAZARDS IDENTIFICATION Clear acidic solution. Pungent chlorine odor. Toxic by inhalation and ingestion. Severely corrosive to all body tissues, especially skin and eyes. Avoid all body contact. Health-2, Flammability-0, Reactivity-2, Exposure-3, Storage-3. 0 is low hazard, 3 is high hazard SECTION 4 FIRST AID MEASURES Call a physician and seek medical attention for further treatment, observation, and support after first aid. Inhalation: Remove to fresh air at once. If breathing has stopped, give artificial respiration immediately. Eye: Immediately flush with fresh water for at least 15 minutes. External: Wash continuously with fresh water for at least 15 minutes. Internal: Give large quantities of water or milk, followed by a gastric antacid, such as milk of magnesia. Do not induce vomiting. Call a physician or poison control at once. SECTION 5 FIRE FIGHTING MEASURES Nonflammable liquid. When heated to decomposition, emits toxic fumes of HCl and Cl2 or explosive H2 gas. Fire Fighting Instructions: Use a triclass, dry chemical fire extinguisher. Firefighters should wear PPE and SCBA with full facepiece operated in positive pressure mode. NFPA CODE: None established. SECTION 6 ACCIDENTAL RELEASE MEASURES Restrict unprotected personnel from the area. Remove all ignition sources and ventilate area. Contain the spill with sand or other inert absorbent material, neutralize with sodium bicarbonate or calcium hydroxide, and deposit in a sealed bag or container. See Sections 8 and 13 for further information. SECTION 7 HANDLING AND STORAGE Flinn Suggested Chemical Storage Pattern: Inorganic #9. Store with inorganic acids. Store in a dedicated acid cabinet and away from any source of water; if an acid cabinet is not available, store in Flinn Saf-Cube. Use and dispense in a hood or in a well-ventilated lab only. SECTION 8 EXPOSURE CONTROLS, PERSONAL PROTECTION Avoid contact with eyes, skin, and clothing. Wear chemical splash goggles, chemical-resistant gloves, and chemical-resistant apron. Use ventilation to keep airborne concentrations below exposure limits. Always wear a NIOSH-approved respirator with proper cartridges or a positive pressure, airsupplied respirator when handling this material in emergency situations (spill or fire). SECTION 9 PHYSICAL AND CHEMICAL PROPERTIES Clear fuming liquid with a pungent odor. Solubility: Soluble in water and alcohol. Formula: HCl Formula Weight: ph < 1 SECTION 10 STABILITY AND REACTIVITY Avoid contact with (Reacts violently with) strong oxidizers, bases, metals, metal oxides, hydroxides, amines, and other alkaline materials. Incompatible with cyanides, sulfides, and formaldehyde. Corrodes metal, including steel. Produces heat and may splatter violently when diluted with water. Shelf Life: Good, if stored safely. SECTION 11 TOXICOLOGICAL INFORMATION Acute effects: Poison, corrosive. Chronic effects: Corrosive to teeth. Target organs: Respiratory tract, teeth, skin SECTION 12 ECOLOGICAL INFORMATION Does not biodegrade in soil, may be toxic to aquatic life. SECTION 13 DISPOSAL CONSIDERATIONS Please consult with state and local regulations. Flinn Suggested Disposal Method #24b is an option. SECTION 14 TRANSPORT INFORMATION Shipping Name: Hydrochloric acid Hazard Class: 8, Corrosive UN Number: UN1789 SECTION 15 REGULATORY INFORMATION TSCA-listed, EINECS-listed ( ), RCRA code D002

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