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Pure Substances/Mixtures & Acid/Bases

Pure Substances/Mixtures & Acid/Bases Benchmark SC.8.P.8.5  Recognize that there are a finite SC.8.P.8.8  Identify basic examples of and compare and classify the properties of compounds, including acids, bases, and salts. ESSENTIAL QUESTIONS:

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Pure Substances/Mixtures & Acid/Bases

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  1. Pure Substances/Mixtures & Acid/Bases • Benchmark SC.8.P.8.5Recognize that there are a finite SC.8.P.8.8 Identify basic examples of and compare and classify the properties of compounds, including acids, bases, and salts. • ESSENTIAL QUESTIONS: • How can you differentiate between pure substances, mixtures, and solutions? • What are the characteristics of acids, bases, and salts?

  2. Bellringer Susie wants to make lemonade on a hot summer day. She mixes lemon juice, water, and sugar in a large container. Which of the following happens as she combines the ingredients? • They mix together to form a new compound. • They mix together to form a homogenous solution. • The stirring motion causes them to break down into elements. • The heavier items will not completely dissolve, creating a suspension.

  3. Pure Substance • Pure Substances can be an element from the periodic table or two or more elements chemically bonded together.

  4. PS: Element • These are chunks of all of the same type of atoms. • You can easily identify elements because they are found on the periodic table.

  5. PS: Compounds • When two or more DIFFERENT elements are combined chemically by being bonded. • Compounds turn into a new substance with completely new properties. • EX. Sodium is a silvery substance that will explode when placed in water. Chlorine is a green gas that will dissolve your lungs. When they bond, they form salt which is completely different. = +

  6. Mixtures: When two or more substances are combined physically (in the same place), but not chemically bonded together.

  7. HETEROgeneous Mixtures: • Two or more substances that are combined PHYSICALLY, but not chemically bonded.You get DIFFERENT amounts in each sample. • Example: • Chex Mix • Italian Dressing • Concrete

  8. HOMOgeneous Mixtures (Solutions) • When one substance is dissolved throughout another substance in equal amounts. You get the SAME amounts in each sample. • Example: • Coffee • Air • Sweet Tea

  9. How do you change the color of hydrangeas?

  10. Acids & Bases They are everywhere.. In your food In your house EVEN IN YOU!!!!!

  11. What is an acid? • An acid is a solution that has an excess of H+ ions. It comes from the Latin word acidus that means "sharp" or "sour". • The more H + ions, the more acidic the solution.

  12. Properties of an Acid • Tastes Sour • Conduct Electricity • Corrosive, which means they break down certain substances. Many acids can corrode fabric, skin, and paper • Some acids react strongly with metals • Turns blue litmus paper red Picture from BBC Revision Bites http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_bases_1.shtml

  13. Uses of Acids • Acetic Acid = Vinegar • Citric Acid = lemons, limes, & oranges. It is in many sour candies such as lemonhead & sour patch. • Ascorbic acid = Vitamin C which your body needs to function. • Sulfuric acid is used in the production of fertilizers, steel, paints, and plastics. • Car batteries

  14. What is a base? • A base is a solution that has an excess of OH- ions. • Another word for base is alkali. • Bases are substances that can accept hydrogen ions

  15. Properties of a Base • Feel Slippery • Taste Bitter • Corrosive • Can conduct electricity. (Think alkaline batteries.) • Do not react with metals. • Turns red litmus paper blue.

  16. Uses of Bases • Bases give soaps, ammonia, and many other cleaning products some of their useful properties. • The OH- ions interact strongly with certain substances, such as dirt and grease. • Chalk and oven cleaner are examples of familiar products that contain bases. • Your blood is a basic solution.

  17. pH Scale • pHis a measure of how acidic or basic a solution is. • The pH scale ranges from 0 to 14. • Acidic solutions have pH values below 7 • A solution with a pH of 0 is very acidic. • A solution with a pH of 7 is neutral. • Pure water has a pH of 7. • Basic solutions have pH values above 7.

  18. Acid – Base Reactions • A reaction between an acid and a base is called neutralization. An acid-base mixture is not as acidic or basic as the individual starting solutions.

  19. Salts • Salts (not table salt) result when an acid and a base neutralize each other (cancel each other out).

  20. Acid – Base reactions • Each salt listed in this table can be formed by the reaction between an acid and a base.

  21. Acids and Bases Compare and ContrastDirections:Classify the various descriptions as being a characteristic of an acidor a base/alkaline

  22. Exit Ticket Before today’s science class, Jose thought that salt was something that he uses to season his French fries. What is the scientific definition of “a salt”? • when fat molecules are suspended in a solution • the result when an acid and base are combined • the particles that settle at the bottom of a solution • when the pH of a solution is lower than 7 but higher than 3

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