How are elements, compounds, and mixtures related? Objective: Describe the difference between pure substances (elements and compounds) and mixtures

What is Matter? Matter is anything that has mass and takes up space (volume) There are different types of Matter: Pure Substances (elements and compounds) and Mixtures The composition (structure) of a substance determines its Matter type.

Characteristics of Pure Substances What does this mean? Fixed composition Distinct properties Cannot be separated into simpler substances by physical methods Can only be changed in identity and properties by chemical methods Properties do not vary one sample to another sample

Types of Pure Substances: Elements And Compounds

Sample of the Element Lead Sample of the Element Chlorine Elements Made up of one type of atom Cannot be broken down by physical and chemical methods Examples: Oxygen, Nitrogen, Carbon Sample of the Element Lead Sample of the Element Chlorine

Compounds Form when two or more different elements join (bond) together chemically Composition is identical in each sample Can be separated only by chemical methods Properties of a compound are totally different than the properties of the elements that form them Examples: Water, Carbon dioxide, Sugar Animated images and notes from http://www.chem.purdue.edu/gchelp/atoms/elements.html

Compounds

Elements and Compounds Study Jams Video http://studyjams.scholastic.com/studyjams/jams/science/matter/elements-and-compounds.htm

Mixtures Form when elements and/or compounds are combined physically Composition varies from sample to sample Can be separated by physical methods Examples of Mixtures: Tea, Perfume, Air, Salad, Beach sand, oil and vinegar salad dressing, etc.

Mixture of Different Elements Mixture of Different Compounds Mixtures Mixture of Different Elements Mixture of Different Compounds

Match the Picture to the Description Compound of 2 Elements Mixture of Molecules Element Molecule Compound of 3 Elements Element/ Atoms Mixture of Atoms

Summarizing: C. A. B. D. Mixture Compound The diagram below shows how two elements can be mixed together…Which is a Compound? A Mixture? A. B. C. D. Compound Mixture

Mixtures are often referred to as homogeneous or heterogeneous.

Mixtures Homogeneous mixtures (Solutions) have a uniform distribution. For example: Tea, Perfume, Air

Mixtures Heterogeneous mixtures do not have a uniform distribution. Parts are often visible For example: Salad, Beach Sand, Oil and Vinegar dressing

Mixtures Study Jams Video http://studyjams.scholastic.com/studyjams/jams/science/matter/mixtures.htm

Determine if the box Contains element only, Compound, or mixture.

DO NOW What are the two types of mixtures? Homogeneous and heterogeneous Give example of each.

Heterogeneous Mixture: unevenly blended Chicken soup- has chunks Yogurt with fruit- has chunks Bowl of cereal Homogeneous Mixture: evenly blended Salt and pepper shaken together Sugar in Kool-Aid © per8

Heterogeneous or Homogeneous mixture: This is a mixture of sand and water: This is a mixture of salt and water:

Mixtures Combinations of substances that can be separated by physical means. Just about everything that you can think of is probably a mixture. Even the purest of materials still contain other compounds as impurities Evenly Blended HOMOgeneous SOLUTIONS are homogeneous mixtures. HETEROgeneous UnEvenly Blended

Solution A homogeneous mixture. One substance is dissolved in another. Salt in salt water Iced Tea mix in water Blue in the toilet bowl Food coloring in water Air ! Metal Alloys (Brass, Bronze, Steel) Watered down vinegar Soda !

Air is a solution of many different gases. Oxygen Hydrogen Nitrogen Carbon Dioxide

TYPES OF SOLUTIONS 1. Gas – Example: air is a solution of different gasses. 2. Solid in a Liquid – Example: Salt water which is in the liquid state. 3. Gas in a liquid – Example: Carbonated beverage. 4. Solid – brass and bronze

Making a Solution How many parts are there to a solution? Two! The liquid and the material you are adding. Ex: water and iced tea What do you do to make a solution? Add the solid material to the liquid and stir.

Water is an excellent solvent. Solute vs Solvent Solvent: The dissolver. The liquid that dissolves other substances. Solute: The substance being dissolved. Water is an excellent solvent.

Using Nail Polish Remover Solvent = Nail Polish Remover Solute = Nail Polish

How much will dissolve? The concentration of a solution tells you how much solute is present compared to the amount of solvent. Which is more concentrated? 100 mg sugar in 1000 ml of water 500 mg sugar in 1000 ml of water

Solubility The ability of a given solute to dissolve in a solvent. The resulting solution is called a saturated solution

Degree of saturation Unsaturated Solution Less than the maximum amount of solute for that temperature is dissolved in the solvent. No solid remains in flask. IPC-Solutions-Borders

Degree of saturation Saturated solution Solvent holds as much solute as is possible at that temperature. Undissolved solid remains in flask. IPC-Solutions-Borders

Precipitate The leftover solute that cannot be dissolved and falls to the bottom of the container is called the precipitate.

Saturated Solution IPC-Solutions-Borders

Do now: What are the three ways to make a solution more soluble?

Factors That Affect Solubility What can be done to make the sugar dissolve faster? 1. Increase Temperature Hotter = Faster Stirring Increase Surface Area More surface area = Faster

Surface Area Which will dissolve faster? A B

precipitate

Graphing Solubility: Temp vs grams solute in 100 grams H2O Generally, the solubility of solid solutes in liquid solvents increases with increasing temperature. IPC-Solutions-Borders Chemistry-Borders

Affect of temperature on solubility of gases The opposite is true of gases. Higher temperature drives gases out of solution. Carbonated soft drinks are more “bubbly” if stored in the refrigerator. Warm lakes have less O2 dissolved in them than cool lakes. IPC-Solutions-Borders

Separating Mixtures Each part of a mixture retains its properties and therefore can be separated.

Separating Mixtures ...how could you separate this mixture? Mixing sulphur and iron... ...how could you separate this mixture?

Separating Mixtures

How can you separate the pulp from the Oj? Filtration: Separating a solid from a liquid

Can you separate salt water? Evaporation! Water Evaporating dish Mixture (salt and water) Salt Bunsen burner

Separating Mixtures: Distillation What is happening here? Water Vapour Mixture (salt and water) Bunsen burner Water

Filtration, Evaporation and Distillation http://www.bbc.co.uk/learningzone/clips/separating-mixtures- of-materials/2295.html

Separation of a Mixture Activity

Original Mixture Mixture The Mass of the Mixture is the Difference

Extraction Mass

Filtration Mass

Evaporation Mass The Mass of the Salt is the Difference

Mass of the Mixture Before % Error (Mass of the Mixture After Separation – Mass of the Mixture Before Separation) x 100 Mass of the Mixture Before = % ( - ) g x 100 ( ) g

Analysis/Conclusion In addition to our usual conclusion… Include: Description of the techniques used. Physical properties we utilized. Why was there a difference before and after separation? …