9/29 Do Now Write 3 facts you know about atoms Write 3 facts you know about elements or the Periodic Table

9/29 Agenda Do Now and review Review your Density Lab Start Chapter 2: Atoms and Elements HW: None

Chapter 2 Classifying Matter

Chapter 2 – Introduction Atoms and Elements

An Element A basic substance that cannot be simplified These are Pure Substances - (always 100% that element) Example: Oxygen, hydrogen, copper, gold, carbon, aluminum These are listed on the Periodic Table

Elements Mankind has discovered 100+ totally unique elements Each element has a name and mass Each element looks and acts different from other elements We abbreviate elements by letters

The atom The smallest unit of an element Every atom is some kind of element Every element has an atom of slightly different size No 2 atoms are identical – (unless they are the same element)

10/2 Do Now List 3 things about atoms, elements, and the periodic table that you learned in class Friday. Be specific! No 1-2 word answers Be honest! Only pick things that you actually learned new yesterday.

Agenda 10/2 Do Now Go over the test New Notes HW: Pages 1 and 2 Pure, Compounds, Mixtures Chemical and Physical Properties Identifying Chemical and Physical changes HW: Pages 1 and 2 Learning Objectives: Identify objects as a type of mixture

Some things to notice… Sometimes, atoms of these elements are alone: Ex: Pure gold, pure aluminum, pure iron Sometimes, atoms of these elements can be combined, to make totally new substances!! Ex: Sugar (C6H12O6), H2O, CO2 ***Notice, there is no element for “water” - H2O*** How do elements combine……?

Bonds A tiny attractive force that joins 2 atoms together

A molecule Made any time 2 or more atoms are bonded together Can be 2 atoms of the same element, or 2 atoms of different elements Ex: H2, O2, CO, CO2

A Compound Name for a type of molecule which is made from more than one kind of element Ex: O2 is NOT a compound …You must have 2+ different elements

Identify the substance Your Label Observe the samples provided. Label the 10 substances in the beakers as: An Element A Compound A mixture of Elements A mixture of Compounds A mixture of Elements AND Compounds

Chapter 2, Continued 2.1 Classifying Matter

Classifying Items People classify objects for different reasons. Classifying food into groups, such as grains, vegetables, and fruits help people plan meals that maintain a healthy diet. Biologists classify organisms into groups that have similar characteristics, which makes the relationships among organisms easier to see. Devise a classification system for the following items: orange, lime, plum, apple, pear, rose, violet, daisy, gold, and silver. Explain what criteria you used to place items into each category of your classification system.

2.1 Classifying Matter Examples: Pure substances- Matter that always has exactly the same composition. There is a fixed, uniform composition. Substances can be classified into two categories: Elements A substance that cannot be broken down into simpler substances. There are just over 100 elements. Atom- The smallest particle of an element. An element has a fixed composition because it contains only one type of atom. No two elements contain the same type of atom. Examples:

Pure Substances Con’t. Compounds A substance made from two or more simpler substances and can be broken down into those simpler substances. The properties of a compound differ from those of the substances from which it is made. A compound always contains two or more elements joined in a fixed proportion.

Mixtures Mixtures tend to retain some of the properties of their individual substances. The properties of a mixture can vary because the composition of a mixture is not fixed. Heterogeneous Mixtures - The parts of the mixture are noticeably different from one another. Examples: salads, salsa

Mixtures Homogeneous Mixtures - The substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another. Examples: steel, salt water

In your own words… …Explain the difference between a pure substance and a mixture. …Explain the difference between a heterogeneous mixture and homogeneous mixture.

10/3 Do Now Write the word that matches the statement: The building blocks of all matter. _________________________ A substance that cannot be broken down into simpler substances. _______________ Compounds and elements have a ________ composition. Is pancake batter a heterogenous or homogeneous type of mixture? ________

10/5 Agenda HW: pg 7 Quiz Friday on Vocab Do Now Nuts and bolts Classifying Matter Activity Solutions, suspensions, colloids Notes HW: pg 7 Quiz Friday on Vocab Learning Objectives: Differentiate between solutions, suspensions, and colloids

Solutions, Suspensions, and Colloids 3 Types of Mixtures Solutions, Suspensions, and Colloids Small particles Large Particles Intermediate particles

Solutions, Suspensions, and Colloids Based on the size of its largest particles, a mixture can be classified as a solution, suspension, or colloid. Solution- Substances dissolve and form a homogeneous mixture. Small particles Examples: tap water, windshield-wiper fluid. Suspensions- Heterogeneous mixture that separates into layers over time. Large Particles. Examples: sand and water, oil and vinegar.

Solutions, Suspensions, & Colloids Colloids- Contains some particles that are intermediate in size between the small particles of solutions and the large particles of suspensions. Colloids will not separate and cannot be filtered. However, colloids will scatter light. (Tyndall Effect) Example: fog

Section 2.2

Section 2.2 Physical Properties Physical property- Any characteristic of a material that can be observed or measured without changing the composition of the substance in the material. Examples: viscosity, conductivity, malleability, hardness, melting point, boiling point, and density.

Physical Properties Viscosity- The tendency of a liquid to keep from flowing. A resistance to flowing. Example: Honey has a high viscosity. Conductivity- A material’s ability to allow heat to flow. Example: Metal spoon over a stove. Materials with a high conductivity are called conductors. They are also a good conductor of electricity as well. Wood is a poor conductor.

Physical Properties Malleability- The ability of a solid to be hammered into thin sheets without shattering. Example: Most metals can be made into coins or foil. Because gold is both malleable and beautiful, it is often used to make jewelry. These ancient gold medallions were made to form a necklace

Physical Properties  Hardness- One way to compare harness of two materials is to see which of the materials can scratch the other. Stainless steel knife blades can scratch copper. Diamond is the hardest known material. This Tlingit carver is using an adze to carve a canoe from Western red cedar. Red cedar is a relatively soft wood

Physical Properties Melting Point- Temperature at which a substance changes from a solid to a liquid. Example: Ice melts because the melting point of water is 0ºC (32ºF).  Boiling Point- Temperature at which a substance changes from a liquid to a gas or vapor. The table lists the melting points and boiling points for several substances.

Physical Properties  Density- Ratio of the mass of a substance to its volume. This can be used to test the purity of a substance. Examples: Silver has a density of 10.5 g/cm3.

Why are these Properties Important? Using physical properties helps us….

Properties: An ID for elements

Using Physical Properties Physical properties are used to 1) identify a material, 2) to choose a material for a specific purpose, or 3) to separate the substances in a mixture. 1) Using properties to identify materials First, decide which properties to test Second, do tests on the unknown sample Third, compare results with a known sample (This is used in crime scene investigations) 2) Using properties to choose materials Properties determine which materials are chosen for which uses. Example: shoelaces wouldn’t be made from wood.

Using Physical Properties 3. Using properties to separate mixtures Filtration and distillation are two common separation methods. Filtration- A process that separates materials based on the size of their particles. Example: brewing coffee Distillation- A process that separates the substances in a solution based on their boiling points. Example: Separate freshwater from seawater.

Recognizing Physical Changes Physical change- Occurs when some of the properties of a material change, but the material itself stays the same . Examples: cutting paper, melting butter.

2.3 Chemical Properties Chemical property- Any ability to produce a change on the composition of matter.  Chemical properties can only be observed when a material is changing into a different substances. Examples: flammability and reactivity.

Chemical Properties Flammability- A material’s ability to burn in the presence of oxygen. Examples: Anything that can be lit on fire or explode. Wood, gas, paper. Reactivity- Describes how readily a substance combines chemically with other substances. Example: Iron with oxygen and water will form rust. If you leave your bike out in the rain.

Recognizing a Chemical Change Chemical change- Occurs when a substance reacts and form one or more new substances. Examples: baking cakes, food digesting. Three common types of evidence for a chemical change are 1) change in color 2) production of a gas 3) formation of a precipitate.

Evidence for a Chemical Change 1) Color Change Silver bracelets will darken “ Tarnishing” Matches burn and turn black. Copper roofs turn green.

Evidence for a Chemical Change 2) Production of a gas Mixing vinegar with baking soda (carbon dioxide gas) Cakes have gas bubbles in it

Evidence for a Chemical Change 3) Formation of a precipitate Precipitate- Solids form and separate from a liquid mixture Exampled: Curdling of milk- adding lemon juice

Is a Change Chemical or Physical? Sometimes gas bubbles or color change is not a chemical change. You must ask yourself: Are different substances present after the change takes place. When matter undergoes a chemical change, the composition of the matter changes. It turns into a NEW thing. When matter undergoes a physical change, the composition of the matter remains the same. A blacksmith uses a hammer to shape a horseshoe that has been heated. Although the color of the iron horseshoe changes, no chemical change is occurring

For each action, write if this is a Physical or Chemical Change Perfume evaporating on your skin   Boiling  Burn (combustion)  Condensation  Charcoal heating a grill  Butter melting  Rust on an old car  Autumn leaves changing color  Crushing a can  Freezing water  Hot glass cracking when placed in cold water Explosion  Grinding coffee beans  Wood rotting  Worksheet “Chem-Phys Prop Wrksht”

Solvent vs Solute These are the 2 parts of a “solution” Solute: The solid molecule which gets “dissolved” Solvent: The liquid the solid is placed into Mnemonic: Solvent = vents in a pool of water

Do Now 10/6 For each action, write if this is a Physical or Chemical Change firewood burning   A rotisserie chicken is cooked in the oven A piece of chalk making chalk dust  Alcohol burning Mold growing on strawberries  Frost forming on grass  Tarnishing silver 

10/6 Agenda Do Now Go Over HW Quiz Lab: Describing and Identifying Matter No HW

Do Now 10/7 How can you tell if a physical change has taken place? How can you tell if a chemical change has taken place? What happens to you if you’re caught not wearing goggles in the lab?

NO HW Test Tuesday! 10/7 Agenda Do Now Hand in Do Now Lab TODAY! Lab Safety Pre lab Questions *Do The Lab* *changes* Post Lab questions/analogies Begin Study Guide NO HW Test Tuesday!

Do Now 10/10 ______ is when metal or some material is molded or shaped ______ is when a material can allow heat to flow through it g/mL is a unit for ______ ______ is when solids are separated from other solids Solutions, suspensions, and colloids are identified by the size of their ____________

Test Tomorrow!! 10/10 Agenda Do Now Kahoot Begin Study Guide Multiple Choice Fill in the blank (like the quiz, but NOT word bank!) Study the words on your quiz, and more! 4 Density math problems – Show all work with our process!

Schedule Wed Finish notes Thurs Quiz / Classification of matter stations lab Fri Physical/Chemical changes of matter lab Monday Review Tuesday Test Test Mystery Powders lab