Make a Unit Cover Page for Unit 2: Chemistry on your next open page in your notebook immediately when you enter the room. Title the next page, “Chapter 2 Pre-Test.”

Write These Questions and Answers in Your Notebook Chapter Pre-test: 1. What instrument would you use to measure temperature? Thermometer 2. Which of the following is a unit of volume? A. atmosphere B. gram C. meter D. liter 3. What characteristic of matter can you measure using a graduated cylinder? 4. The sides of a cube are 2 cm by 2 cm. What is the volume of the cube? 5. What additional quantity would you need to calculate the density of the cube in question 4? 6. Which of the following topics is not studied in chemistry? A. Composition of matter B. reactions of substances C. properties of materials D. motion of large objects.

Answers Chapter Pre-test: 1. What instrument would you use to measure temperature? Thermometer 2. Which of the following is a unit of volume? A. atmosphere B. gram C. meter D. liter D. 3. What characteristic of matter can you measure using a graduated cylinder? Volume 4. The sides of a cube are 2 cm by 2 cm. What is the volume of the cube? 8 cm3 5. What additional quantity would you need to calculate the density of the cube in question 4? Mass 6. Which of the following topics is not studied in chemistry? A. Composition of matter B. reactions of substances C. properties of materials D. motion of large objects. D.

Physical science Chapter 2 Properties of Matter

Lab Each group will be provided 4 materials, a rubber band, a steel paper clip, a copper prong, and wooden pencil or toothpick. Determine the properties or characteristics of the materials by touching, smelling, and looking at them. Record these properties in a table/chart. After you record these properties, write a description of each material that could be used to clearly identify it. Only take from 5-10 minutes

Possibilities Rubber’s elasticity Copper’s color Steel’s shininess Wood’s brittleness Description: Copper is a gold-ish solid that is flexible enough to be shaped and bent

Section objectives 1. Classify pure substances as elements or compounds. 2. Understand why elements and compounds are classified as pure substances 3. Understand how mixtures differ from pure substances. 4. Know what the main difference is among solutions, suspensions, and colloids.

Heterogeneous mixture Matter Substance Element Compound Mixture Heterogeneous mixture Homogenous Mixture

Intro A tendency to wrinkle is a property of cotton, the tendency to not wrinkle is a tendency of polyester, the tendency to shrink when washed is a property of wool. Why do different clothing materials have different properties? Different substances have different properties based on the elements and compounds that make them up!

Pure substances Matter that always has the same composition is classified as a pure substance, or substance Every sample of a given substance has the same properties because a substance has a fixed, uniform composition. Salt is a composition of sodium and chloride Substances can be classified into two categories, elements and compounds Matter Substance Elements Compounds

Elements There are only about 100 elements Element: a substance that cannot be broken down into simpler substances An atom is the smallest particle of an element An element has a fixed composition because it contains only one type of atom.

Elements No two elements contain the same type of atom. Most elements are solids at room temperature (20 C, 68 F)

Examples of Elements Aluminum

Example Carbon

Elements Some elements are gas at room temperature Oxygen and nitrogen are the main gases we breathe

Liquid Elements Only two elements are liquid at room temperature: Bromine and mercury, both are very poisonous

Symbols (don’t write) The symbols for elements are similar to why scientists use the SI system of measurement. Why do you think? Many symbols are based on the Latin name for the element and all scientists agree on the symbol for each element *project!: Choose an element you are unfamiliar with. Research the origin of the symbol. Then, research the application or use of the element. Write at least a paragraph detailing this information and turn it in on Friday

Compounds A compound is a substance that is made from two or more simpler substances. The simpler substances are either elements or other compounds

Compounds continued THE PROPERTIES OF A COMPOUND DIFFER FROM THOSE OF THE SUBSTANCES FROM WHICH IT IS MADE Water is a compound made up of the elements hydrogen (H) and oxygen (O) Both of these elements are gases at room temperature, but water is a liquid Hydrogen can fuel a fire and oxygen is needed to keep it going, but water is used to put it out

COMPOUNDS COMPOUNDS ALWAYS CONTAIN TWO OR MORE ELEMENTS JOINED IN A FIXED PORTION/POSITION Silicon dioxide, for example, is the compound found in most light colored sand It is made from the elements silicon ( a gray solid) and oxygen. It is always made with two oxygen atoms for each silicon atom. (di means 2)

Mixtures Mixtures tend to retain some of the properties of their individual substances But the properties of a mixture are less constant than the properties of a substance The properties of a mixture can vary because the composition of a mixture is not fixed.

On your own Read pages 41-44 Create a chart in your notebook with descriptive visuals and examples to help you classify the different types of mixtures Heterogeneous Homogeneous Solutions Suspension Colloid When you finish, complete section 1 in your workbook. Write the answers in your notebook.

Types of mixtures Mixtures are combinations of substances The composition of the substances (unlike compounds) are not constant Example: salsa Heterogeneous mixtures: the parts that make up the mixture are noticeably different Example: sand

Bellwork Think of a homogeneous and a hetergeneous mixture

Heterogeneous Mixtures Hetero (different) genus (kind)

Homogeneous mixtures Homogeneous mixtures: the substances are so evenly distributed that it is difficult to distinguish one substance from another Example: a stainless steel spoon is a homogeneous mixture of iron, chromium and nickel

Homogeneous Mixtures

Solutions, Suspensions, Colloids Based on the size of its largest particles, a mixture can be classified as a solution, suspension, or a colloid

Solution Solution: when substances dissolve and form a homogeneous mixture Example: sugar dissolved in water Characteristics: Particles are too small to settle out of the solution Particles cannot be trapped by a filter Particles are too small to scatter light

Solution

Suspension “Shake Well” Suspension: a heterogeneous mixture that separates into layers over time Example: Sand and water Characteristics: Particles will settle Particles can be filtered Particles are large enough to scatter light

Suspension

Colloid Colloid: contains some particles that are intermediate in size between the small particles in a solution and the larger particles in a suspension. Example: homogeneous milk Characteristics: Particles do not separate into layers You cannot filter to separate parts of a colloid Particles are large enough to scatter light

Colloid

Mixture Solution Suspension Colloid Heterogeneous Homogeneous Combination of substances Solution When substances dissolve in a homogeneous mixture, sugar water Suspension Heterogeneous mixture that separates into layers, sand and water Colloid Homogeneous mixture with intermediate particles, milk, fog Heterogeneous Parts are noticeably different , sand Homogeneous Parts are evenly distributed, stainless steel spoon

Examples of physical properties Physical property: any characteristic of a material that can be observed or measured without changing the composition of the substances in the material. Viscosity Conductivity Malleability Hardness Melting point Boiling point Density

Viscosity Viscosity: the tendency of a liquid to keep from flowing-its resistance to flowing The greater the viscosity the slower the liquid flows

Viscosity usually decreases when heated Importance? Think motor oil… https://www.youtube.com/watch?v=x0Y9XJvHwD0

Conductivity Conductivity: a material’s ability to allow heat to flow Materials with high conductivity are conductors If a material is a good conductor of heat it will usually do the same for electricity So why do we stir soup with a wooden spoon?

Conductive materials https://www.youtube.com/watch?v=4WillWjxRWw

Malleability Malleability: the ability of a solid to be hammered without shattering. Most metals are malleable Solids that shatter when struck are brittle Give an example of a malleable and brittle material.

Malleability https://www.youtube.com/watch?v=c382ziUpbbc

To compare hardness you can try to scratch one object with another Hardness: how hard a material is To compare hardness you can try to scratch one object with another Diamond is the hardest material known

Hardness

Melting and boiling points Melting Point: The temperature at which a substance changes from a solid to liquid Boiling Point: The temperature at which a substance boils What are the melting and boiling points of water in Celsius?

Boiling point https://www.youtube.com/watch?v=nVr9WdPjJ-s Melting Point https://www.youtube.com/watch?v=pVTZySPJh5w

Melting/Boiling Points

Density Density: can be used to test the purity of a substance Examples include methanol for bike racing

Homework Finish section 1 packet