Integrated Science Chapter 2: Matter

1. Integrated Science Chapter 2:Matter

2. Ch. 2-1: What is Matter? Key Terms Chemistry Matter Mass Element Atom Compound Molecule Chemical Formula Pure Substance Mixture

3. California Content Standards for Science Addressed: Chemistry 1. The periodic table displays the elements in increasing atomic number and shows how periodicity of the physical and chemical properties of the elements relates to atomic structure. 2. Biological, chemical, and physical properties of matter result from the ability of atoms to form bonds from electrostatic forces between electrons and protons and between atoms and molecules. 3. The conservation of atoms in chemical reactions leads to the principle of conservation of matter and the ability to calculate the mass of products and reactants. 10(a). Students know large molecules (polymers), such as proteins, nucleic acids, and starch, are formed by repetitive combinations of simple subunits.

4. Ch. 2-1:Why Do I Need To Know This? Because we are all made up of matter. Because the type of matter matters. Because not all types of matter are the same.

5. Key Sections Ch. 2-1 What is Matter? Composition of Matter Atoms are Matter Elements Combine to Form a Compound Compounds have Unique Properties A Mixture Acts as a Unit Chemical Formulas Represent Compounds and Molecules Pure Substances and Mixtures Mixtures are Formed By Mixing Pure Substances Mixtures are Classified By How Thoroughly the Substances Mix

6. What is Matter? Chemistry is the scientific field that studies the composition, structure, and properties of matter and the changes that matter undergoes. The scientific field that studies how matter how all matter and energy moves is called physics and is covered in Integrated Science Semester 2!

7. Composition of Matter Matter is anything that has mass and takes up space. This means that it has a volume. Mass is the measure of how much �stuff� is in something. Mass is the same everywhere throughout the universe. Mass is different from an object�s weight which is NOT the same everywhere in the universe. Everything that you can touch is made up of matter. Matter can exist in 4 states which we will learn more about in chapter 3!

8. Atoms Are Matter An element is a substance that cannot be broken down into simpler substances by chemical means. Each element has its own set of unique properties. An atom is the smallest unit of an element that retains all of the properties of that element. In chemistry, elements are represented by 1 or 2 letter symbols to identify them. Some examples are H for Hydrogen, O for Oxygen and Al for Aluminum. All chemical symbols start with a CAPITAL LETTER and then a lower case letter (if necessary).

9. Elements Combine Chemically To Form A Compound A compound is a substance made up of two or more different elements that are chemically combined. Most things in the universe are compounds.

10. Compounds Have Unique Properties Compounds have unique properties that are different from the properties of the elements that they contain. For example, both Hydrogen and Oxygen are colorless gases at room temperature, but, when they combine, they can form water, which is a liquid at the same temperature. When elements combine to form a specific compound, they elements always combine in the same ratios and in the same manner. For example, water found anywhere in the universe will be made up of 2 atoms of Hydrogen combined with 1 atom of Oxygen. The atoms in the water compound will always be in the same shape.

11. A Molecule Acts As A Unit A molecule is the smallest unit of a substance that keeps all of the physical and chemical properties of that substance. Molecules are made up of 2 or more atoms that are chemically combined. Unlike a compound, a molecule can be made up of atoms of only one element. Oxygen is a good example of this: A single atom of oxygen can react with atoms of other elements to form compounds. Oxygen can react with a single atom of Oxygen to form a molecule of oxygen that we breath in the air. Oxygen can also react with 2 other atoms of oxygen to form a molecule of ozone which is poisonous for us to breath.

12. A Molecule Acts As A Unit Compounds are typically formed by repeating patterns of elements that move as units. DNA is an example of a very long compound made up of repeating units. In the DNA molecule, the repeating units are long acids, sugars, and phosphates.

13. Chemical Formulas Represent Compounds and Molecules In order to describe molecules, chemists use chemical formulas to represent the molecules. A chemical formula shows the different elements and the number of atoms for each element in a compound. In a chemical formula, a subscript number (after the chemical symbol) tells us how many atoms are present for that element. If there is no number after the chemical symbol, then we assume that there is only 1 atom of that element. Additionally, numbers in front of the molecule (called coefficients) tell us how many molecules are present. This is like an algebra problem with a variable! H20 C16H10N2O2 7H2O

14. Pure Substances and Mixtures A pure substance is matter that has a fixed composition and definite properties. A mixture is a combination of 2 or more substances that are not chemically combined Therefore a mixture does not have a fixed composition or definite properties. Unlike compounds, mixtures can be easily separated into their basic components.

15. Mixtures Are Formed By Mixing Pure Substances A mixture may have properties that are similar to the components from which it is made. For example, both coffee and milk are liquids. Coffee is brown and milk is white. When mixed, they both remain liquids and the color will change depending on how much coffee or milk is in the mixture.

16. Mixtures are Classified By How Thoroughly the Substances Mix Mixtures are classified by how thoroughly mixed they are. Mixtures that are completely mixed evenly are called homogenous mixtures. Fruit punch and soda pop are examples of homogenous mixtures. Mixtures that are not evenly mixed are called heterogeneous mixtures. Cheese and crackers are examples of heterogeneous mixtures. Substances that can dissolve in liquids are said to be miscible. Sugar and water are miscible. Substances that cannot dissolve in liquids are said to be immiscible. Oil and water are examples of immiscible liquids.

17. Ch. 2-2: Properties of Matter Key Terms Melting Point Boiling Point Density Reactivity Flammability

18. California Content Standards for Science Addressed: Chemistry 1. The periodic table displays the elements in increasing atomic number and shows how periodicity of the physical and chemical properties of the elements relates to atomic structure. 2. Biological, chemical, and physical properties of matter result from the ability of atoms to form bonds from electrostatic forces between electrons and protons and between atoms and molecules. 3. The conservation of atoms in chemical reactions leads to the principle of conservation of matter and the ability to calculate the mass of products and reactants.

19. Ch. 2-2:Why Do I Need To Know This? Because everything that exists has physical and chemical properties that we use to classify it. Because the physical properties of a substance determine its uses. Because the chemical properties of a substance also determine its uses.

20. Key Sections Ch. 2-2 Properties of Matter Physical Properties Physical Properties Describe Matter Density is a Physical Property Density is Often Measures in Unites of g/cm3 Physical Properties Help Determine Uses Chemical Properties Chemical Properties Describe How A Substance Reacts Comparing Physical and Chemical Properties Characteristic Properties Help to Identify and Classify Substances

21. Properties of Matter Most substances that exist in the universe are compounds. Chemistry identifies and explains the properties of all substances that exist. Chemistry identifies properties as either physical properties or chemical properties. The combination of the a substance�s physical and chemical properties determine the uses for the substance.

22. Physical Properties Physical properties are those properties that are typically very easy to observe. Physical properties are generally those properties that can be detected with one or more of your senses. Matter can be described by either the presence or the absence of a physical property. For example, some things like air are described as being colorless.

23. Physical Properties Describe Matter There are many physical properties used to identify matter. They include Mass Volume Density Shape Color Odor Texture Melting Point Boiling Point Strength Ability to Conduct Electricity Ability to Conduct Heat Magnetism Physical State (solid, liquid, gas, or plasma)

24. Physical Properties Describe Matter For pure substances, the physical properties do not change regardless of how much or how little of it you have. Pure water is colorless regardless of how much of it you have. Some physical properties are considered characteristic properties. These include melting point, boiling point and density. For pure substances, characteristic properties never change if the temperature and pressure remain the same and can be used to identify the substance.

25. Density is a Physical Property Density determines whether an object will float or sink. Generally speaking, a less dense object will always float over a more dense object. An object�s density can change based on the object�s volume. However, a substance�s density will never change. For example, iron is more dense then water, but, when stretched and made into a ship, will float on water because of all the trapped air in it. Since heat causes most objects to expand, they gain in volume and become less dense. This is how hot air balloons work.

26. Density is a Physical Property Density is the measurement of how much matter is contained in a certain volume. Generally speaking, things that are more dense feel �heavy�. However, weight is NOT density. Weight is the measurement of gravity�s pull on the object. Two substances with the same amount of mass will have different densities. A pound of feathers takes up more volume than a pound of steel, so the feathers will be less dense than the steel. Density determines whether an object will float or sink.

27. Density is Often Measured in Units of g/cm3 The density of water is 1.0 g/cm3, but this only occurs at about 4� C. Ice must be less dense than water because ice floats in water. If ice did not float in liquid water, there would be no life on Earth. In the metric system, 1 cm3 is equal to 1 mL. 1.0 mL of water is defined to have the mass of 1.0 g. The formula for density is D=M/V. Using this formula, you can determine an object�s mass or volume if you know the density and one of the two missing bits of information. To determine an object�s mass, the formula is M=VD. To determine an object�s volume, the formula is V=M/D.

28. Physical Properties Help Determine Uses The physical properties of a substance determine a lot of its uses. Industry tries to find new uses for existing substances or find new substances to meet changing needs. In some cases, we have created new elements and materials that do not otherwise exist in nature. Manmade materials are called synthetic materials.

29. Chemical Properties A substance�s chemical properties are those properties that determine how it will react with another substance. Not all substances react with other substances. Some substances do not react with anything in the universe. Substances that do not react at all are said to be inert. In many cases, changing the temperature, pressure, or other factors may affect a substance�s chemical properties. Generally speaking, chemical properties are not as easy to observe as physical properties.

30. Chemical Properties Describe How A Substance Reacts The chemical properties of a substance depend on the elements that make up the substance. Two useful chemical properties are reactivity and flammability. Reactivity is the ability of a substance to combine chemically with another substance. When substances react, atoms from elements within the substances swap places and make new compounds. Flammability is the ability of a substance to react in the presence of oxygen and burn when exposed to a flame. A substance always has its chemical properties, regardless of how much of the substance you have.

31. Comparing Physical and Chemical Properties Physical properties are different from chemical properties in that they can be observed without changing the identity of the substance. To identify a chemical property, you must destroy it in a chemical reaction. Chemical properties do not change based on how much or how little of the substance is present. Some physical properties can change (such as mass or color) depending upon how much of the substance you have. Just because two substances have similar physical properties, they may have totally different chemical properties. Both salt and sugar have similar physical properties (both produce white crystals), but they have very different chemical properties (as you can tell by tasting them).

32. Characteristic Properties Help to Identify and Classify Substances Scientists use certain physical and chemical properties to identify and classify all substances. These properties are called characteristic properties. Characteristic properties for a substance do not change whether the amount of the substance is large or small. The three most useful characteristic properties are: Density Solubility Reactivity with Acids

33. Ch. 2-3: Changes of Matter Key Terms Physical Change Chemical Change

34. California Content Standards for Science Addressed: Chemistry 1. The periodic table displays the elements in increasing atomic number and shows how periodicity of the physical and chemical properties of the elements relates to atomic structure. 2. Biological, chemical, and physical properties of matter result from the ability of atoms to form bonds from electrostatic forces between electrons and protons and between atoms and molecules. 3. The conservation of atoms in chemical reactions leads to the principle of conservation of matter and the ability to calculate the mass of products and reactants.

35. Key Sections Ch. 2-3 Changes of Matter Physical Changes Physical Changes Do Not Change a Substance�s Identity Dissolving is a Physical Change Mixtures Can Be Physically Separated Chemical Changes Chemical Changes Happen Everywhere Chemical Changes Form New Substances That Have Different Properties Chemical Changes Can Be Detected Chemical Changes Cannot Be Reversed By Physical Changes Compounds Can Be Broken Apart Through Chemical Changes

36. Ch. 2-3:Why Do I Need To Know This? Because we rely on physical and chemical changes daily in our lives. Because physical changes are a part of many cycles in nature. Because we create many useful substances by chemically reacting other substances.

37. Changes of Matter Some materials benefit us because they stay in the same state (solid, liquid, gas, or plasma) and do not change states easily. Other materials benefit us because they change states easily. The physical and chemical properties of a substance determine how the substance will behave under different conditions.

38. Physical Changes A physical change affects one or more physical properties of a substance without changing its identity. For example, if you cut a piece of chalk in half, both halves would still have all the properties of chalk. This would be true until you get down to the basic molecule of chalk. Some examples of physical changes include: Melting Boiling Freezing Evaporating Ionizing Dissolving Cutting Crushing

39. Physical Changes Do Not Change A Substance�s Identity During a physical change, energy is either absorbed or released. However, during the physical change, the arrangement of the atoms that make up the substance does not change. In most cases, a physical change can be reversed by physical means.

40. Dissolving is a Physical Change Although it appears that when you mix sugar with water that the sugar disappears, it does not. When a substance gets dissolved, the substance that is dissolved gets spread out throughout the fluid that dissolves it. Since the molecules for neither the fluid nor the substance being dissolved changes, dissolving is a physical change.

41. Mixtures Can Be Physically Separated Since mixtures are not chemically combined, they can be separated through physical means. Some common ways to separate mixtures are; Filters Distillation Evaporation Factionalization Magnetism Spinning (use of a centrifuge) Again, none of these changes alters the atoms or molecules in the substances.

42. Chemical Changes A chemical change is a change that occurs when a substance changes its composition by forming one or more new substances. Many substances are useful because they react easily or under certain circumstances. Gasoline and gunpowder are both useful because they react with oxygen very easily and quickly produce gases that have large volumes in the reaction. This results in the original substance being destroyed.

43. Chemical Changes Happen Everywhere Chemical reactions occur everywhere. When you breathe in and out, a chemical reaction occurs in your lungs. When food ripens or spoils, a chemical reaction occurs. When a piece of iron rusts, a chemical change occurs.

44. Chemical Changes Form New Substances That Have Different Properties When a chemical change occurs, the original substances are completely destroyed and new substances are created. An example is baking a cake. When you bake a cake, all the ingredients in the batter combine to form the cake. The properties of the cake are quite different from the properties of the ingredients.

45. Chemical Changes Can Be Detected When a chemical change occurs, there often are several clues that the change occurred. Some common ways to identify that a chemical change is occurring are: Change of Color Fizzing Foaming Production of Heat Production of Sound Production of Light Production of Odor

46. Chemical Changes Cannot Be Reversed By Physical Changes Since chemical changes create new substances, you cannot reverse them. For example, you cannot unbake a cake to get the eggs, flower, sugar, milk, and oil back. Some chemical changes can be reversed under certain circumstances by other chemical changes. For example, the chemical reactions in a rechargeable battery that create the electricity can be reversed by charging the battery up again with more electricity. The most common ways of reversing chemical reactions are to either add heat, pressure or electricity to the new compounds.

47. Compounds Can Be Broken Down By Chemical Changes Often many compounds can be broken down into smaller compounds or elements during a chemical reaction. If you ever made a volcano in school, when you combine vinegar and baking soda, the compounds break down releasing hydrogen gas. We will learn more about chemical reactions in Chapter 6!