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Mixtures

This article explains the definitions of compounds and mixtures, their characteristics, and methods for separating them. It also covers the pH scale, acids, and bases.

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Mixtures

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  1. Mixtures Spring 2011

  2. Compounds Vs. Mixtures • Compound Definition: Two or more different elements chemically bonded by a chemical reaction to form a new substance. • Examples: NaCl, H2O, CO2 • How can they be broken down or separated?: Compounds can only be broken down or separated by chemical means. (it requires a chemical reaction to break them apart).

  3. Compounds Vs. Mixtures • Mixtures Definition: a combination of two or more substances that are not chemically combined. • Examples: salad, kool-aid, blood, salt water • How can they be broken down or separated?:Mixtures can be broken down physically. No chemical reaction is required.

  4. Characteristics of Mixtures • No chemical change occurs(the • substances keep their identity). B.THE SUBSTANCES CAN BE SEPARATED!!!!!

  5. Atoms vs. Elements vs. Compounds vs. Mixtures

  6. Types of Mixtures • Heterogeneous- the different • substances are visible in the mixture. • Homogeneous – The mixture looks the same and has the same characteristics throughout.

  7. Types of Heterogeneous mixtures a. Suspension: mixtures in which particles of a material are dispersed throughout a liquid or gas but are large enough that they settle out.

  8. Types of Homogenous Mixtures • Solution: A mixture that looks to be the same but is composed of 2 or more substances • appears to be a single substance. • Examples: Alloys, soda, salt water, tea.

  9. Types of Homogeneous Mixtures • Colloid: a mixtures in which the particles are dispersed (spread) throughout but are not heavy enough to settle out. • Examples: Milk, mayonnaise, stick deodorant, shaving cream, and jello are all colloids. Colloids are like a mix between solutions and suspensions

  10. Parts of a Solution • Solute: is the substance that is dissolved. • Ex. Salt, sugar. • Solvent: is the substance in which the solute is dissolved in. • Does the • dissolving • Ex. Water.

  11. Solubility=the ability of an object to dissolve into other substances. Solubility of Solids and Temperature Change: Solubility of solids increases as temperature increases. Solubility of Gases and Temperature Change: Solubility of gases decreases as temperature increases.

  12. Separating Mixtures Suppose you had a mixture of iron nails, salt and water… How would you separate this mixture completely? Based on which physical properties would you base your method on?

  13. Ways Mixtures Can Be Separated Filtration – Used to separate heterogeneous mixtures composed of liquids and solids Using some form of filter to separate particles that won’t dissolve from a liquid. This is good for separating an insoluble solid from a liquid (an insoluble substance does not dissolve in water). EX: sand can be separated from a mixture of sand and water Using filtration

  14. Evaporation – Used when you wish to collect a solute from a solution. Evaporate a LIQUID to leave the SOLID behind.

  15. Separating Mixtures Continued Distillation: the process that separate a mixture based on the boiling points of the components. Used to separate Homogeneous mixtures

  16. Chromatography – used to separate out mixtures of dyes. Shows all the colors used to make certain dyes or pigments ink stain

  17. Acids & Bases

  18. Foldable Instructions • Get a piece of paper and fold “hamburger style”. • Fold “hamburger style” again. • Cut the TOP half of the paper up to the “mountain”. • Label one side “ACID” and the other side “BASE”. • The inside of the flaps should contain your notes on acids, bases, and the pH scale. Follow along with PowerPoint.

  19. Our Goals for today • To determine the difference between Acids & Bases • Discuss the importance of studying Acids & Bases • Perform an experiment dealing with Acids & Bases

  20. Characteristics Of Acids Acids can be characterized by: • A sour taste. Try drinking lemon juice (citric acid) • It turns litmus paper red • Have a pH from 0-7, the lower the pH number the stronger the acid… • They can neutralize (chemical reaction) a base. • They are corrosive (eat through things).

  21. Characteristics of Bases A Base is characterized by: • A bitter taste. (TUMS) • It feels slippery. (Soapy Water) • It turns Red Litmus Blue. • Have a pH from 7-14, the higher the pH number, the stronger the base. • Can neutralize (chemical reaction) an acid.

  22. What is the pH scale? • The pH scale measures how acidic or basica mixture is.

  23. Draw a pH scale in your foldable. You do NOT have to draw the pictures, but you should include some examples of acids and bases on your scale.

  24. Identifying Acids and Bases • Acids have a ph from 0-7 • Lower pH value indicates a stronger acid. • Bases have a pH from 7-14 • Higher pH value indicates a stronger base.

  25. Did we Miss something?? • What happens when the pH of a substance is 7? • Ans: A pH level of 7 indicates a Neutral Substance i.e: Water! • Neutral- is neither an acid nor a base. • Neutralization- chemical reaction between an acid and a base to form a neutral substance (salts).

  26. Why Learn about Acids & Bases? • What do you think is the pH level of NYC tap water? • The pH of a swimming pool must be checked periodically. Why? • Is it important for Lakes & Rivers to maintain a certain pH?

  27. Today’s Experiment • Test the pH of Pepsi, tap water, and drain cleaner • On the back of your foldable copy the chart below to record your observations about acids and bases. • GOOD LUCK!!!

  28. Bellringer #1 • The smallest part of matter is: a. Cell b. Particle c. Molecule d. Atom • To find information about elements: a. Look at a dictionary b. Use a periodic table c. Google them d. Look under a microscope • Vocabulary words are: a. Any word you don’t know b. Words that may help me understand a concept better c. Important to all subject areas. d. All of the above.

  29. Bellringer #2 • 1. A mixture where you can see the individual parts is called a: a. Homogenous mixture b. Solution c. Colloid d. Heterogeneous mixture • 2. A mixture where you cannot see the individual parts is called a: a. Homogenous mixture b. Suspension c. Heterogeneous mixture d. Compound • 3. The main difference between compounds and mixtures is: a. Compounds can be separated but mixtures cannot. b. Compounds do not require a chemical reaction to occur. c. Mixtures can be separated by physical means. d. Mixtures require a chemical reaction.

  30. Bellringer #3 • 1. A solute is: • The liquid that a solid or gas is dissolved into. • The solid or gas that is dissolved. • Is greater than the solvent. 2. A solvent is: a. The liquid that a solid or gas is dissolved into. b. The solid or gas that dissolved. c. Is less than the solute. 3. A solution is: a. A homogenous mixture b. A mixture with a solute and solvent c. Both A and B

  31. Bellringer #4 • 1. When you balance chemical equations: a. The atoms are equal on both sides of the equation. b. There are more atoms on the reactant side of the equation. c. There are more atoms on the product side of the equation. • Solubility of solids: a. Increases with a decrease in temperature. b. Increases with an increase in temperature. c. Decreases with an increase in temperature. • The two main types of mixtures are: a. Heterogeneous and homogenous b. Solutions and suspensions c. Solute and solvent

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