Period 4 Period 5 Period 6 Describing Matter

Period 4 Period 5 Period 6 Describing Matter (2. 1) The Nature of Matter Changes in Matter (2. 2) Energy and Matter(2. 3) Cha pte r 2 Just the Facts

Chapter 2 – Self Check 1. Get out Chapter 2 info sheet 3. Read and mark your facts and definitions. Need more practice Have a question Feel confident

Ch 2 Practice Points Workbook Answer the questions that you find interesting or challenging. Answer at least one question from each section. Read all the questions. 1 point for each correct answer. Chemical vs. Physical Properties: Make a Venn diagram to compare and contrast physical and chemical properties. Include at least 5 unique points for each and 3 similarities. Law of Conservation of Matter Classroom Display: Research Antoine Lavoisier. Create a classroom display using pictures and writing to describe the experiments he performed that were the basis for the law of conservation of matter. Energy Extend Assignment: Make a slide show presentation that explains each of the 4 types of energy describe in your textbook. Be sure to include text and pictures on each slide. Use appropriate vocabulary. Vocabulary Flash Cards: Make flash cards with word, definition, and picture for each of the 10 essential words for this chapter.

Chapter 2 Vocabulary Matter Physical Property Chemical Property Element Atom Chemical Bond Molecule Compound Chemical Formula 1. 2. 3. 4. Law of Conservation of Matter Solution VOCAB CLASSWORK Physical Change Fold your paper into 16 boxes Chemical Change Pick 16 words In each box include: Energy • Correctly spelled word Thermal Energy • Glossary definition Endothermic Change • Picture to help you remember definition Exothermic Change • An example Chemical Energy This note page should be used for studying to prepare for Friday’s quiz and next Friday’s chapter 2 Test.

1: Properties of Matter 2: Elements 3: Compounds 4: Mixtures Describing Matter Section 2. 1 Page 58

Forms of Matter What are some examples? Matter (takes up space and has mass) All Mixed Up Mixture (2+ substances, not chemically bonded, no set ratio) Heterogeneous (parts visible) Homogeneous (parts indistinguishable) Pure Substance (single kind of matter with distinct properties) Element (types of atoms) Molecule (2+ atoms) Compound (2+ elements)

Fact 1: Properties of Matter Physical Properties • Can be observed without changing it into another substance • Examples: – Read page 60 • Density • Magnetism Discuss • – Melting pointat table • Conductivity • Texture Luster – List on note • page • Color • Hardness • Flexibility Prop. Quiz Show Chemical Properties • Describes ability to change into different substances • Must observe through experimentation, not just by looking or touching • Flammable • Examples: • Can Tarnish • Can Rust Test Tube Detective

Fact 5: Ch-Ch-Ch-Changes Physical Changes Chemical Changes • Alters form or appearance • Does not change the substance • Examples – Change in State • Transforms the substance into a different substance • Substance breaks down • Substances combine • Examples A substance that undergoes a – To Liquid – To Solid change is physical – To Gas • Examples – Change in Form still the same – Dissolving – Bending substance after – Crushing change. –the Breaking – Chopping A chemical change produces new – Chemical reaction with substances – Combustion (burning) – Oxidation (metal reacts with properties different oxygen) – Tarnishing (metal reacts with from those of the sulfur) – Electrolysis (electricity breaks original substances. down a substance)

Fact 6: Energy • All physical or chemical changes involve absorption or release of energy – Endothermic = absorbs energy Endothermic vs. Exothermic – Exothermic = releases energy • Types of Energy: – Thermal (movement of molecules, heat) – Chemical (stored in chemical bonds) – Electromagnetic (wave energy, light) – Electrical (movement of charged particles)

A Couple of Laws • Law of Conservation of Matter/Mass: Matter is not created or destroyed during chemical or physical changes; it just changes form • Law of Conservation of Energy: Energy cannot be created or destroyed; it can just change form.

Sorting Activity 1. Look at the cards in your bag. 2. With your table, sort them into physical changes or chemical changes. 3. Make sure everyone in your group agrees 4. Participate with the class to check your answers 5. Record the examples on your note page Physical Change Examples Chemical Change Examples Check your Answers Hold up PINK for PHYSICAL CHANGE Hold up BLUE for CHEMICAL CHANGE

Elements, Compounds, and Mixtures 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Compound (B) Mixture of Elements (C) Mixture of Compounds and Elements (E) Mixture of Compounds (D) Element (A) Compound (B) Element (A) Mixture of Compounds and Elements (E) Mixture of Elements (C) Mixture of Compounds and Elements (E) Compound (B) Mixture of Compounds (D)

Substance vs. Mixtures 1. 2. 3. 4. 5. Sodium – Na – Element Water – H 2 O – Compound Soil – Mixture Oxygen – O – Element Alcohol - CH 3 CH 2 OH – Compound 6. Carbon Dioxide – CO 2 – Compound 7. Cake Batter – Mixture 8. Air - Mixture 9. Soup – Mixture 10. Salt Water – Mixture 11. Ice Cream – Mixture 12. Nitrogen – N – Element 13. Eggs – Mixture 14. Blood – Mixture 15. Table Salt – Na. Cl – Compound 16. Cola - Mixture

Heterogeneous vs. Homogeneous 1. Flat Soda Pop – Homogeneous 2. Cherry Vanilla Ice Cream – Heterogeneous 3. Salad Dressing – Heterogeneous (usually) 4. Sugar Water – Homogeneous 5. Skip 6. Spaghetti Sauce – Heterogeneous (usually) 7. Soil – Heterogeneous 8. Paint – Homogeneous 9. Pure Air – Homogeneous 10. City Air – Heterogeneous 11. Coffee – Homogeneous 12. Steel - Homogeneous

Toasty Marshmallow Lab • Purpose: Observed chemical changes caused by changes in energy. • Background: Define endothermic and exothermic change. • Data: Temperature of Water Before Temperature of Water After

Toasty Marshmallows – p 73 1. Add 20 m. L water to an empty soda can and record temperature. 2. Place the mini marshmallow on the paperclip contraption. 3. Hold the can of water over the marshmallow. USE TONGS. 4. Light the marshmallow and wait for it to completely burn. 5. Record the temperature of the water.

Toasty Marshmallows Analysis • Conclusion: Use paragraph format and address all questions. – Did the temperature of the water change? Why? – What evidence of a chemical change did you observe? – What kind of energy was released? – Where was the energy originally stored? – Was the reaction exothermic or endothermic?

Matter n Anything that has mass and takes up space n All the “stuff” around you is matter n Matter can be divided into two categories: mixtures and pure substances

Pure Substances n Substances that are a single kind of matter n Always has the same make up and properties no matter where it comes from n Ex: table salt- always comes from seawater or a salt mine

Elements n. A pure substance that CANNOT be broken down into any other substance n They are the simplest substance n Ex: carbon, calcium

Compound n Made up of two or more elements chemically combined n Ex: Water- hydrogen and oxygen

Mixtures n Made up of two or more substances (elements or compounds) but they DO NOT chemically combine n They CAN be separated & r u o l F ar Granite Rock Chocolat e & Water

Heterogeneous Mixture n You can see the different parts n Separate the parts easily n Ex: Salad or sand flour

Homogenous Mix - Solutions n. A very well mixed mixture n Can’t see or tell that there are different parts even though there are n Ex: sugar water – can’t tell the sugar from the water after mixing

Practice Questions Try to answer without looking at your notes or reviewing the previous slides n Once you decide on an answer, go back and see if you were right. n

Question 1: What would salt water be considered? a. An element b. A compound c. A solution or homogenous mixture d. A heterogeneous mixture

Question 2: Which is an example of a heterogeneous mixture? a. Fruit punch b. Sand rocks c. Sugar water d. Kool-Aid

Question 3: Matter can be divided into two categories, what are they? Mixtures and Pure Substances

All Mixed Up Homogenous vs. Heterogeneous Mixtures • Purpose: How can you tell a homogeneous mixture from a heterogeneous mixture? (What will you do? ) • Background: What is a heterogeneous mixture? What is a homogeneous mixture? (Describe each type of mixture) Discuss answers at your table, then record onto your lab report.

All Mixed Up • Procedure: Carefully look at each test tube and record your observations. You may smell (waft) but don’t taste. • Data: (Copy this data table onto your lab report) Test Tube 1 2 3 4 5 6 Substance Well Mixed or Separated? Heterogeneous or Homogeneous Mixture?

All Mixed Up • Conclusion: What is the main difference between homogeneous and heterogeneous mixtures? What sense do you use to determine whether a mixture if homogeneous or heterogeneous?

All Mixed Up: Test Tubes 1 2 3 4 5 6

Test Tube Detective • Purpose: Observe physical and chemical properties to identify an unknown sample. • Background: What is a chemical property? What is a physical property? List examples of each. Discuss answers at your table, then record onto your lab report.

Test Tube Detective • Procedure: 1. Observe and record physical properties: what does it look like (use magnifier), what does it feel like, what does it smell like (waft!) 2. Start with baking soda, put 0. 5 m. L into each test tube. Then add a dropper full of vinegar, water, iodine into the corresponding test tube. Record observations 3. Clean out test tubes and repeat with each of the remaining known samples. 4. Perform the same test on the unknown sample. 5. Identify the unknown by comparing to your observations of the known samples.

Test Tube Detectives – Data Table Substance Baking Soda Baking Powder Cornstarch Baby Powder Unknown Physical Properties Chemical Property with Vinegar Chemical Property with Water Chemical Property with Iodine

Test Tube Detectives • Conclusion – What physical properties did you observe? – What chemical properties did you observe? – What is the identity of your unknown substance? – What properties helped you determine the unknown?

Chemical vs. Physical Changes

Physical Changes, P. 68 -72 l l l Physical changes involve altering the form of a substance, but does not change it to another substance. Ex: bending a nail, tearing paper, making playdough changing states of matter – boiling water, freezing popsicle, mixing koolaid, etc…

Changes of State l l All changes of state are physical changes. All state changes involve loss or gain of thermal energy

Chemical Changes Defined l l During a chemical change, matter is changed into a new substance with new properties. Ex: burning wood – wood to ash and gases Other examples: baking a cake, glow sticks, making toast, mixing vinegar and baking soda, milk ‘curdling’, etc… Think of a chemical change of when you can’t change the new substance back to it’s original form.

Chemical Changes l l l Chemical changes = chemical reactions In all chemical reactions, new substances are produced. All reactions either release or absorb energy. Ex: of absorption – plant growth, cold packs. Ex: of release – digestion, baking, lighting a match, burning wood

Law of Conservation of Matter l l Matter is not created or destroyed in any chemical or physical change. Mass of reactants always equals the mass of the products

Energy and Change l l During physical and chemical changes, energy is either added or taken away. Thermal energy is energy from molecule movement (heat) Chemical energy is the energy from the bonds between molecules in a substance. Law of conservation of energy – during any chem. Or phys. Change, amount of energy stays the same.

Examples of conservation of Energy l l l Unlit match contains chemical energy When lit – energy converted to thermal and light energy. Amount of energy remains the same, just changes form.