Friday, Aug. 30 th “A” Day Tuesday, Sept. 3 rd : “B” Day Agenda  Discuss lab questions/finish/collect Begin Ch 1: “The Science of Chemistry”  Section 1.1: “What is Chemistry?” Physical states of matter/Properties of matter Changes in matter (physical & chemical) Evidence of chemical changes Homework: 1. Sec. 1.1 review, pg. 9: # Concept review: “What is Chemistry?” (Due on day of chapter test)

Lab: “Lab Techniques”  Questions on Analysis questions 1-3?  Questions on Conclusion questions 4-6?

Lab: “Lab Techniques”  Conclusion question #7: “Drawing conclusions”  The density of any material is its mass divided by its volume. Density = Mass (g) Volume (mL)

Lab: “Lab Techniques” 1.Calculate the density of water by using your data from step #11. 2.You have 3 pairs of mass/volume data from step #11:  ? grams water / 50 mL of water  ? grams water / 100 mL of water  ? grams water / 150 mL of water 3.Find the density of water for each pair of data. 4.You will have 3 different values for the density of water from step #11 data.

Lab: “Lab Techniques” 1.Do the same thing to calculate the density of water by using your data from step #12. 2.Calculate your average density for both steps #11 and #12. 3.The actual value for the density of water at 25°C is: g/mL. How close did you get?

Lab: “Lab Techniques”  Put the “Lab Techniques” lab, with your lab write-up stapled to the front, in your lab folder behind the table of contents on the right-hand side.  Put your folder in the bin for your class period.  Once graded, the folders will be returned to the bin with comments and the completed lab rubric.

Chapter 1: “The Science of Chemistry” Sec 1.1: “What is Chemistry?”  Chemistry: a science that deals with the properties of chemicals and with the changes chemicals can undergo.  Chemical: any substance that has a defined composition – it’s always made of the same stuff no matter where the chemical comes from. Some chemicals exist naturally. Which ones? Some are manufactured. Which ones?

You Depend on Chemicals Every Day  Many people think of chemicals in negative terms (all chemicals are bad), but you depend on chemicals every day of your life.  Look at the list of ingredients in your shampoo or toothpaste tomorrow morning. You’ll see a lot of chemicals listed.  The air you breathe, the food you eat, and the water that you drink are all made up of chemicals!

Chemical Reactions Happen All Around You  Chemical reaction: the process by which one or more substances change to produce one or more different substances.  Chemical reactions take place all around you, and inside of you, every day.  Examples of chemical reactions: cooking food, striking a match, starting an engine, turning on a flashlight, etc.

Physical States of Matter  States of Matter: the physical forms of matter, which are… Solid Liquid Gas Plasma

Properties of the Physical States  Solid Fixed (definite) volume, fixed shape Rigid structure Vibrates only slightly  Liquid Fixed (definite) volume but NOT fixed shape Liquids flow and take the shape of their container Particles are not held together as strongly as in a solid and can slide past one another

Properties of the Physical States  Gases Neither fixed volume nor fixed shape Particles weakly attract one another and move independently at high speed Will fill any container they occupy as the gas particles move apart  Plasma A gas whose particles have been broken apart and are charged

Water in Three States  Macroscopic: what you can see naturally  Microscopic: what you would see if you could see individual atoms (think “microscope”)

Changes of Matter  Changes of matter are classified into 2 broad categories: Physical changes Chemical changes

Changes of Matter  Physical changes: Changes where the identity of the substance doesn’t change. **Changes of state are physical changes.** Ice, liquid water, and steam are all still H 2 O.  Examples: dissolving sugar in tea, crushing a rock.

Changes of Matter  Chemical changes: the identities of the substances change and new substances are formed. Example: 2 H 2 + O 2 2 H 2 O H 2 and O 2 are both gases at room temperature, but H 2 0 is a liquid.

Reactants and Products 2 H 2 + O 2 2 H 2 O  Reactants: a substance or molecule that participates in a chemical reaction Reactants are on the left side of the arrow. Reactants are used up in the reaction.  Products: a substance that forms in a chemical reaction Products are on the right side of the arrow. Products are made in the reaction.

Evidence of Chemical Change 1.The evolution of a gas a)Bubbling, change in odor 2.The formation of a precipitate a)2 clear solutions are mixed and become cloudy 3.The release or absorption of energy a)A change in temperature or the giving off of light energy 4.A color change in the reaction system a)A different color when 2 chemicals react

Evidence of a Chemical Change

Homework  Sec. 1.1 Review, pg. 9: #1-10  Concept Review: “What is Chemistry?” Concept Review packet will be due on the day of the Chapter 1 test…..

Looking Ahead  Next class: Section 1.1 Quiz: “What is Chemistry?” Wednesday, Sept. 4 th High School Open House 6:30 – 8:00 p.m.