Introduction to Matter Pages 6-15 “K”

1. Introduction to MatterPages 6-15 “K”

2. Matter is anything that has mass and takes up space • Everything around us is matter. • You and I are matter too! • Yes—it is true.

3. What are the properties of matter? • Rough • Gray • Small • Sharp • Brown • Hollow • Hard

4. Properties describe . . . . . . . • You could add gas, liquid, solid, hot, cold, soft, and the list goes on and on and on and on. • Every form of matter has two kinds of properties—physical properties and chemical properties.

5. Chemistry is the study of the properties of matter and how matter changes. • Matter will change depending on its makeup. • Example: Lets look at oxygen. A physical property is that it is a gas at room temperature. • A chemical property of oxygen is that it reacts with iron to from rust.

6. Physical property/physical change • When dealing with physical properties, or change, the properties of the pure substance can be observed without changing it into another substance. • Example:

7. Substance • Is a single kind of matter that is pure. It has a specific set of properties and makeup. • The following example has definite physical properties and also definite chemical makeup properties:

8. The example: • Table salt. It has the same physical and chemical properties whether it comes from seawater or a salt mine. It is always 39.3% sodium chloride and 60.7% chlorine by mass.

9. What about the batter for blueberry muffins? • What does it have in it? • Blueberries, flour, salt, sugar, eggs, baking soda and baking powder, milk, and butter.

10. So . . . . . . • While the ingredients may be pure substances, the batter is not. • What do we call the batter? • A mixture!

11. Can I separate a mixture? • Turn to page 14-15 K. • Let’s go through those steps and see. • What about the muffin mix? • Nope! Some of it has begun to interact and begin a chemical change. • Afterall, you cannot take all the ingredients and put them back once they are all mixed together and beginning to interact.

12. Two types of mixtures: • Heterogeneous Mixtures: you can see the different parts—like a salad.

13. The other type of mixture: • Homogeneous mixture: these are so evenly mixed that you cannot see the different parts. • Sugar or salt water

14. Remember: all matter has physical and chemical properties. • Water may freeze, thaw, go to steam, condense back to water and refreeze, however, it is still water; is water; is water! • But------ it is a change you say? • Yes, but this is a “phase” change. • The water is in a different phase but it is still water. • Let’s show you a physical change with paper and a two paperclips.

15. This is fun to show you a change that does not change the substances involved • Fold your paper like this:

16. Now hole the two ends of the folded paper and SLOWLY --------- • Pull in opposite directions until the paper is stretched out. • Please Do Not pull quickly. • What happened? • The paper clips are hooked together and the paper is unchanged also. This is a physical change—no one substance is changed. They appear different but they are still paper and paperclips.

17. What are more words to classify physical properties of matter? • Dissolvability, luster, can conduct heat and electricity, magnetism, flexibility (can bend w/o breaking). • Chemical properties-a characteristic of a pure substance that describes its ability to change into different substances.

18. Want an example of a chemical property? • With methane (natural gas) it would be that it can catch fire and burn in the air. • How? As it burns it combines w/ oxygen in the air and forms new substances: water and CO2 (carbon dioxide). • Burning or flamability is a chemical property of methane, as well as the substances in wood or gasoline which can also burn.

19. Another example: Iron and oxygen • What will iron combined with oxygen produce? • Good old rust! • What about silver and sulfur in the air? • Tarnish which makes ugly silver.

20. What do bakers use to produce a chemical change in their breads? • Yeast. • The yeast produces a gas and the bread rises. 

21. Let’s try one now: • In the bag I add a chemical and then water. • Changes are occurring. Pass the bag around and tell me what you feel. • A change in temperature to “cold”

22. How do physical properties differ from chemical properties? • Chemical properties must combine with something else to form a new substance=a chemical change (The chemical property cannot always be seen). • Physical properties do not change the substance into something else. (remember the water phase changes). Generally physical properties are descriptions of the substance.

23. What is an element? • An element is a pure substance that cannot be broken down into any other substances by chemical or physical means. • Elements are the simplest substances. • Here is a periodic table for your journal. Let’s look at it and tell you how to read it.

24. What is the smallest piece of the element? • The atom!! • When atoms combine the form a chemical bond. This bond makes a larger particle called a molecule. • Like H2O or CO2 or NACL

25. Compounds • A compound is a pure substance made of two or more elements chemically combined in a set ratio. Looking at CO2 = one carbon atom and 2 oxygen atoms. This is a 1 to 2 ratio. • When elements are chemically combined, they form compounds having properties that are different from those of the uncombined elements.

26. Quick atom review: • What is the positive particle of the atom called and where is it located? • A proton and in the nucleus. • What is spinning quickly out on the far edges of the atoms and what charge are these? • The electrons and the charge is negative. • What particle has no charge at all and where are these found? • A neutron and in the nucleus with the protons.