Name: Unit 2- Elements, Compounds and Mixtures and Physical/Chemical Properties and Changes. Elements, Compounds and Mixtures

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1 Name: Unit 2- Elements, Compounds and Mixtures and Physical/Chemical Properties and Changes Day Page # Description IC/HW All 2 Warm-up IC Matter Notes IC 1 6 Nuts & Bolts IC 1 7 Elements, Compounds and Mixtures IC Physical/Chemical Properties/Changes Notes IC 2 10 Physical and Chemical Properties and Changes Worksheet IC Due Date Completed 2 11 Energy Notes IC X 2, Physical & Chemical Changes Lab HW/IC Unit 2 Review HW 4 X Unit 2 Quiz In class on 9/21 and 9/22 1

2 Warm-up Day 1 1. What is the difference between a homogeneous and heterogeneous mixture? Day 2 Day 3 1. Identify the following as elements, compounds, solutions, or heterogeneous mixtures. a. Copper b. Water c. Steel d. Gravel e. Uranium f. Carbon Dioxide 2. State whether each of the following are physical or chemical properties. If they are physical, indicate if they are intensive or extensive. a. Mass b. Volume c. Reactivity d. Boiling Point e. Density 3. Define chemical change and give an example. Day 4 1. If 5.04 g of Hydrogen mixed with Oxygen to form g of water, and 1.00 g of Hydrogen was left over, how much Oxygen reacted? 2

3 Matter Notes Solid Liquid Gas Vapor: is not the same as gas. Vapor refers to the gaseous phase of a substance that is a liquid or solid under standard conditions. Solid Liquid Gas Plasma: high temperature, low pressure; electrons separate from nucleus; most common in the universe Elements: a pure substance that is made up of only one type of atom and cannot be broken down by physical or chemical means. o Examples: Compounds: a combination of two or more different elements that are combined chemically. o Examples: Mixture: a combination of two or more pure substances in which each pure substance retains its physical properties. o Examples: o Homogeneous mixture: Mixtures in which the composition is uniform throughout. Also called a SOLUTION. Examples: 3

4 o Heterogeneous mixture: Mixtures in which the composition is not uniform throughout. You can distinguish the different parts. Examples: Separation of Matter Elements- can only be broken down by nuclear reactions. Compounds- can only be broken down by chemical reactions Mixtures- can be broken down by physical means. Filtration Distillation Chromatography- physical separation based on attraction to liquid or solid. o Paper Chromatography- paper is the stationary phase and liquid is the mobile phase. The more attracted to the mobile phase, the higher up on the paper the substance will move. o Column Chromatography- beads are the stationary phase and liquid is the mobile phase. The more attracted to the mobile phase, the further down the column the substance will move. 4

5 Law of Conservation of Mass- mass can neither be gained nor lost in a chemical reaction. o Chemical Reaction- creates a substance or substances known as the product(s). o Reactants Products o In the complete reaction of g of Sodium with g of chlorine. What mass of sodium chloride will be formed? o A 12.2 g sample of X reacts with sample of Y to form 78.9 g of XY. What is the mass of Y that reacted? 5

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7 Elements, Compounds and Mixtures Practice Classify each of the following as an element, compound, mixture or solution. 1. water 2. oxygen 3. sodium chloride (table salt) 4. sea water 5. gold 6. soil 7. ranch dressing 8. soda 9. milk 10. air 11. steel 12. granite rock 13. hydrogen 14. sugar dissolved in water 15. Kool-Aid 16. potassium 17. filtered apple juice 18. fresh squeezed lemonade 19. arsenic 20. carbon dioxide 7

8 What is matter? Physical/Chemical Properties and Changes Notes Physical Properties: Properties of a substance that can be measured without changing the chemical nature of the substance. o Examples: o Intensive Properties: are of the amount of matter present. o Extensive Properties: are on the amount of matter present. Intensive Extensive 8

9 Chemical Properties: Properties of a substance that cannot be measured without changing the chemical nature of the substance. o Examples: Physical Changes: Changes that do not alter the chemical composition of a substance. o Examples: Chemical Changes: Changes that alter the chemical composition of a substance. o Examples: o Indications of a chemical change: 9

10 Physical and Chemical Properties and Changes Practice Indicate whether the following properties are physical or chemical. If the property is physical, indicate whether the property is intensive or extensive. Property Physical or Chemical Intensive or Extensive H 2 O boils at C Fe rusts The density of Pb is 11 g/ml Na is highly reactive The mass of the sample is 4.5 g Ag will tarnish Hg is a liquid at 25.0 C Al is silvery colored The length of a Cu wire is m Ga will melt in your hand Indicate whether the following changes are physical or chemical. Change Pb melting Frying an egg Chopping wood Boiling H 2 O Cu oxidizing A car bumper rusting Leaves changing color Shredding paper CO 2 subliming Fruit rotting Physical or Chemical 10

11 Energy Notes Energy- the capacity of matter to do work. Potential Energy (PE)- stored energy. Kinetic Energy (KE)- energy of motion. Law of Conservation of Energy- energy can be neither created nor destroyed, but can be transferred into other forms. Heat is a form of energy. Temperature is the direction heat will flow (from hot to cold). Energy is measured in Joules J = 1 calorie (memorize this!) 1 calorie is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius. Specific Heat capacity- the amount of heat needed to raise one gram of a substance by one degree Celsius. c = heat (cal) mass (g) x change in temperature ( o C) Or you can rewrite the equation to solve for heat: o heat = q = (mass) x (specific heat) x (change in temperature) o q = mcδt Heat is energy that moves because of a change in temperature. Chemical energy is released of absorbed during a chemical reaction. Electrical energy comes from the movement of electrons. Radiant energy can travel through empty space (light, UV, infrared, radio). Nuclear energy comes from changing the nucleus of an atom. All types of energy can be converted into each other. All energy started as nuclear energy. 11

12 Physical & Chemical Changes Lab Purpose This experiment will continue your introduction to physical and chemical changes, with an emphasis on learning to make quantitative observations related to chemical change. Prelab Question 1. Explain how you will be able to tell the difference between a chemical change and a physical change. You must include five specific pieces of evidence that will let you know a chemical change has taken place. 2. Look up the MSDS for aluminum. What precautions should you take when working with aluminum? 3. Look up the MSDS for Copper. What precautions should you take when working with Cu? 4. Look up the MSDS for Magnesium Metal. What precautions should you take when working with Mg? Part I Obtain a aluminum wire from the lab cart. Note the physical appearance. Obtain a Bunsen burner from the lab cabinet. Place the aluminum wire in the flame and note whether or not the wire glows. Using the wire, determine where the hottest portion of the flame is. 12

13 1. Draw a diagram of the Bunsen burner flame and use it to answer the first two questions. a. The hottest portion of the flame is located where? b. The cone of gas not on fire is located where? 2. Have the physical properties of the wire changed? Explain Obtain a piece of copper metal and use the steel wool to remove the oxidation from the copper. Using forceps, place the piece of copper metal in the flame of the burner for a couple of minutes. Note the physical appearance of the copper before and after heating. Observations: 3. Did the copper metal undergo a chemical or physical change? Explain. 13

14 Part II In order for the experiments to work correctly your labware must always be clean and dry before being used in an experiment. Also take great care to use only the chemicals called for in an experiment. Reaction of Magnesium. Weigh a crucible and lid to the nearest hundredth of a gram, add about a quarter gram of magnesium metal to the crucible, and weigh again. Record the measurements in data table labeled Data Table 1. Support the crucible on a clay triangle and place the lid on the crucible at an angle so that the magnesium is exposed to the air. Heat gently until the bright glowing of the metal no longer is evident. Cool the crucible and lid for five minutes and weigh again. If the magnesium metal fails to glow, increase the heat. Data Table 1 Mass of crucible and lid Mass of crucible, lid and magnesium Mass of Mg before heating Mass of crucible, lid and Mg after heating Mass of product g g g g g 1. Explain the fact that the mass of the product was more than the mass of the reactant Mg. 2. What pieces of evidence demonstrate that the Mg has undergone a chemical change? 14

15 Unit 2 Review 1. Classify the following materials as heterogeneous mixtures (M), homogeneous mixtures/solution (S), compounds (C) or elements (E). a) air b) ink c) paper d) salt e) ethyl alcohol f) apple g) milk h) plutonium i) water j) ice k) shaving cream l) paint m) granite n) 24 carat gold o) orange juice p) carbonated beverage 2. Classify the following properties as chemical (C) or physical (P). If it is physical, identify if it is intensive (I) or extensive (E). a) color b) reactivity c) flammability b) odor e) porosity f) stability g) ductility h) solubility i) expansion k) rusting l) reacts with air 3. Classify the following as chemical (C) or physical (P) changes. a) digestion of food b) boiling water c) growth of a plant d) explosion of gasoline e) cloud formation f) healing a wound g) burning of coal h) kicking a football i) contracting a muscle j) distilling water k) melting silver l) rusting iron m) subliming of iodine 4. What is the conversion for Joules to Calories? 5. What is the equation for Specific Heat? 15

16 6. Define Specific Heat. 7. What is the difference between heat and temperature? 8. If 3.32 g of carbon and 5.05 g of sulfur react completely. What is the resulting mass of carbon disulfide? 9. If 1.10 g of hydrogen gas reacts with oxygen to produce 4.10 g water, what mass of oxygen must be present? 10. Identify the six phase changes. 11. Define filtration. 12. Define distillation. 13. How can compounds be separated? 14. What are the stationary and mobile phases in paper chromatography? 15. What are the stationary and mobile phases in column chromatography? 16