1. Change & Chemical Properties Well, no…not that kind of change. Yeah…THAT kind of change!

2. Let’s get started on your paper. Let’s title this and update the Table Of Contents. Now here’s the important part. To make this set of notes useful to you, it has to be neat & organized. Notes – Chemical Properties & Change Anything you need to write on your paper in your notes will be in red. So be sure you write the title above and all be sure you write the title above and all the other red you’ll see in these notes.

3. Before we start… Before we start… One of the big goals in 6 th grade science is for you to be able to tell physical properties apart from chemical ones. To do this, you have GOT to know what physical properties are. You have studied a lot of them during your time in Elementary. Can you list some physical properties of yourself or your classmates?

4. So… …what do you think a chemical property is? A chemical property is one you can observe during a chemical reaction. It forms a new substance that wasn’t present when you started. Let’s write that. Key Word???? NEW SUBSTANCE!!!

5. Chemical Properties Notes – Chemical Properties & Change I. Chemical Properties – properties of a substance that can only be observed during a reaction. It always results in a new substance being formed. That’s a pretty long definition, but it’s awfully important to know. ESPECIALLY that 2 nd sentence.

6. Let’s See Some Chemical Properties Let’s say you had a substance. Like a can of gasoline. How could you demonstrate one of its chemical properties? You could…find its density? Nope. Density is a physical property… it does not result in a new substance.

7. What else? What else? Hmm…we could…freeze it? Well, no, not really. Freezing a liquid is just a physical process. It’s not a new substance... just a change in state of matter. Well, how about if we describe the gasoline’s luster? LUSTER???? SERIOUSLY???

8. Oh yeah!

9. Write It! Notes – Chemical Properties & Change I. Chemical Properties – properties of a substance that can only be observed during a reaction. It always results in a new substance being formed. A.Flammability – does the substance burn (react with oxygen to release heat)? Since we’re going to start listing examples of chemical properties,we will indent them and letter them to go under the Roman Numeral I. Indent about the width of your pinky.

10. How About Another Chemical Property? There were a few horror movies made “back in the day” starring these guys: In the movies, one of the things the people quickly realize is that if you cut or damage one of these aliens, it will bleed an acid that would burn through anything it came into contact with…Nasty. Yeah, like that.

11. So What? Those movies have created a myth that ALL acids are super-harmful, extremely dangerous, will eat-through-anything chemicals. Is this really true? Nope… Here are some examples of acids you may be familiar with:

12. Bases Acids (and their opposites…bases) are just reactive chemicals that behave in certain ways. Here are some common bases:

13. Is There a Point To This? Acids and bases are just a few of MANY kinds of chemicals that can react with each other. When chemicals react, they produce new substances. New substances! Chemical change! You’re familiar with baking soda and vinegar, right? They combine… … and react to make new substances (CO 2 gas and other materials)

14. Let’s Write This. Let’s Write This. Notes – Chemical Properties & Change I. Chemical Properties – properties of a substance that can only be observed during a reaction. It always results in a new substance being formed. A.Flammability – does the substance burn (react with oxygen to release heat)? B.Reactivity – does the substance chemically combine with other chemicals, such as acids & bases?

15. Vinegar and Baking Soda is Easy. How else do you tell? Well, there are some common signs to look for to help you determine if a new substance has been formed and they are called INDICATORS. You have to remember that these are signs or indicators that a “chemical change” has occurred, but there are sometimes exceptions. You will always have to think if the reaction you are looking at has FORMED A NEW SUBSTANCE!!

16. Energy Release A chemical reaction often releases forms of energy such as light and heat. Glow sticks work when a capsule of phenyl oxalate is broken (by you) and it mixes with hydrogen peroxide. This releases energy that causes a colored dye to glow with light. When you burn something, the fuel is reacting with oxygen in the air to produce fire–a combination of heat AND light.

17. Back to the Notes… A.Flammability – does the substance burn (react with oxygen to release heat)? B.Reactivity – does the substance chemically combine with other chemicals, such as acids & bases? C.Signs that a chemical change has happened: energy released (heat/light) ex: match burns

18. Yeah, And? Well, back to vinegar and baking soda…the huge release of gas is a good sign that a new substance (the gas, duh) has been produced. Hydrochloric acid creates hydrogen gas when reacting with zinc metal.

19. More Signs… More Signs… A.Flammability – does the substance burn (react with oxygen to release heat)? B.Reactivity – does the substance chemically combine with other chemicals, such as acids & bases? C.Signs that a chemical change has happened: energy released (heat/light) ex: match burns gas or bubbles form ex: vinegar + baking soda  CO 2

20. Ok! What else? A permanent change in color often lets you know that a substance has been chemically, not physically, changed into a new substance. mmm…the perfect cookies

21. #20 A.Flammability – does the substance burn (react with oxygen to release heat)? B.Reactivity – does the substance chemically combine with other chemicals, such as acids & bases? C.Signs that a chemical change has happened: energy released (heat/light) ex: match burns gas or bubbles form ex: vinegar + baking soda  CO 2 permanent color change ex: burning wood changes its color

22. Is there more? Yes. Here’s another one…imagine what this… …smells like. Probably not the way it smelled 10 minutes before being pulled out of the oven. Perfectly good cookies. RUINED.

23. #20 A.Flammability – does the substance burn (react with oxygen to release heat)? B.Reactivity – does the substance chemically combine with other chemicals, such as acids & bases? C.Signs that a chemical change has happened: energy released (heat/light) ex: match burns gas or bubbles form ex: vinegar + baking soda  CO 2 permanent color change ex: burning wood changes its color odor released ex: baking bread creates new gases

24. One Last One… What do the previous four indicators of chemical change have in common? They let you know that a chemical change has happened? Well, yeah, no kidding. BESIDES that?

25. They’re All Hard to Reverse! Yeah! Imagine trying to stuff the heat and light back into a burning candle. Uh huh…ouch. Or imagine trying to get burned cookies to go back to being brown. Or take it another step. Try to get a nicely baked cookie to “unbake” and turn into cookie dough. gee…how ?

26. Irreversibility

27. #20 A.Flammability – does the substance burn (react with oxygen to release heat)? B.Reactivity – does the substance chemically combine with other chemicals, such as acids & bases? C.Signs that a chemical change has happened: energy released (heat/light) ex: match burns gas or bubbles form ex: vinegar + baking soda  CO 2 permanent color change ex: burning wood changes its color odor released ex: baking bread creates new gases difficult to reverse ex: can’t turn a cookie back into dough

28. So… it’s the OTHER kind of change (physical) if… a.does Not release heat or light b.does Not release gas or bubbles c.does Not change the color of something permanently d.does Not release new odors e.is somewhat reversible You can cut, mash, smash, stretch, flatten, divide, shave, freeze, thaw cookie dough and it’s STILL cookie dough. Those kinds of changes haven’t made new substances. A ____ change happens when no new substance is made. The opposite kind of change, a ___ change,DOES create a new substance.

29. And that’s Chemical Properties and Changes… Let’s Add…

30. Physical Changes A.Flammability – does the substance burn (react with oxygen to release heat)? B.Reactivity – does the substance chemically combine with other chemicals, such as acids & bases? C.Signs that a chemical change has happened: energy released (heat/light) ex: match burns gas or bubbles form ex: vinegar + baking soda  CO 2 odor released ex: baking bread creates new gases difficult to reverse ex: can’t turn a cookie back into dough II. Physical Changes – Do not result in a new substance being formed. (changes in size, shape, or state of matter).

31. What are Physical Properties? Well, we know that all matter has mass (it’s made of stuff) and it has volume (takes up an amount of space). It doesn’t matter if it’s a fleaor a whale …it’s made of matter. The most enormous stars and the tiniest, microscopic air molecules are matter, too.

32. Yes, and…? Matter has properties beyond just “mass” and “volume,” right? If I asked you to describe this object here: …you wouldn’t just tell me, “It has a mass of 34 grams and a volume of 23 milliliters.” You’d use words like delicious, gooey, yummy, soft, smells good, and so on and so on. If we want to describe matter, there are a few ways that we use called physical properties. It’s a way to describe a substance WITHOUT saying it changed into a new substance. It’s a physical property!

33. DENSITY Density is a weird one. You know by now that all matter has mass and volume. But density tries to describe how “packed in” the mass is within that volume. In other words, how compact is the stuff? This golf ball and marshmallow are about the same size (volume). But which is going to have more mass? The golf ball has way more mass. Since they’re about the same size, you know that the golf ball has a higher density.

34. Density What’s heavier…a pound of steel or a pound of feathers? Well, a pound is a pound, so they have the same weight. But what would those two piles of objects look like? Hi, Joe. Yo. A pound of steel, yeah. And a pound of feathers. It’s clear steel is WAY more dense than feathers.

35. Back to Our Notes Notes – Physical Properties II. Physical Properties – descriptions of matter that can be observed without changing it into a new substance. A. Density – describes tightly packed the matter is in a substance. A bowling ball is more dense than a beach ball.

36. COLOR Well, it might be pretty simple to say that a frog is green or jeans are blue or Joe is red, but there’s some pretty technical reasons for why things have colors. The point is that you can describe a substance’s color without changing it into a new substance.

37. Write it! Notes – Physical Properties II. Physical Properties – descriptions of matter that can be observed without changing it into a new substance. B. Color – describes how light is absorbed by a substance and what light we see. A. Density – describes tightly packed the matter is in a substance. A bowling ball is more dense than a beach ball.

38. LUSTER Ooohhh…look at that biscuit.Ooohhh…look at this gold ring. I desire the one on the left for its tastiness. I desire the one on the right for its LUSTER. Luster describes how shiny a substance is.

39. Get it on your paper! Notes – Physical Properties II. Physical Properties – descriptions of matter that can be observed without changing it into a new substance. A. Density – describes how compact the matter is in a substance. A bowling ball is more dense than a beach ball. B. Color – describes how light is absorbed by a substance and what light we see. C.Luster – describes how shiny a substance is due to how light reflects off an object.

40. HARDNESS This one can be a little confusing. You’ve probably heard that the hardest substance on Earth is a diamond. That means that a diamond can cut any other substance you can think of, even metals. The only thing that can cut a diamond is a slightly more pure diamond! However, that doesn’t mean that diamonds are stronger than anything else. I’d much rather live in a brick or steel house than a diamond one. Keep your bricks. I’ll take the diamonds!

41. Get it on your paper! Notes – Physical Properties II. Physical Properties – descriptions of matter that can be observed without changing it into a new substance. A. Density – describes how compact the matter is in a substance. A bowling ball is more dense than a beach ball. B. Color – describes how light is absorbed by a substance and what light we see. C.Luster – describes how shiny a substance is due to how light reflects off an object. D.Hardness – describes a substance’s ability to resist shape change. Doesn’t always mean “strength.”

42. CONDUCTIVITY Some substances allow forms of energy, such as heat, sound, and electricity, to flow through them very easily. Apparently, Joe is one of those substances. These substances are very useful for things like:

43. Conductivity But other substances are useful to us because they’re NOT good conductors. We call those insulators. E.Conductivity – describes how well a substance allows heat or electricity to flow through it. Low conductivity substances are called “insulators.”

44. MALLEABILITY What do these substances have in common? If you said that they can be pounded with a mallet or hammer or fist or forehead into new shapes easily, then you’re right! F.Malleability – describes how easily a substance can be formed into new shapes. Opposite of “brittle.”

45. DUCTILITY What do THESE substances have in common? Well, of course…they’re all ductile! That just means they can be stretched or drawn into wires without falling apart or breaking. G.Ductility – describes how well a substance can be pulled into thin wires.

46. MAGNETISM I’m not sure how much to say about this. Some substances are magnetic, others aren’t. H. Magnetism – describes if a substance attracts or repels magnets.

47. STATE OF MATTER STATE OF MATTER A lot of you remembered that matter comes in three states: SOLID LIQUID GAS Whether a substance is solid, liquid, or gas is a physical property. You can easily tell me what it is without having to change the substance. I.State of Matter – describes whether a substance is solid, liquid, or gas.

48. Review All these properties that we described are physical properties. This just means that they are ways that scientists commonly describe substances without having to change them into a new substance. Remember this? You should be able to go down your list of physical properties and decide which this cookie has or doesn’t have. And then eat it!

49. And That’s… And That’s…

50. ©Weston, 2009