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Chapter 5 Lesson 5

Chapter 5 Lesson 5. Compounds and Chemical Changes. What are Compounds ?. A compound is formed by the combination of two or more elements. Compounds have properties different from their elements. Compound (Honey Mustard for your chicken nuggets!!) . Names and Formulas.

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Chapter 5 Lesson 5

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  1. Chapter 5 Lesson 5 Compounds and Chemical Changes

  2. What are Compounds? • A compound is formed by the combination of two or more elements. • Compounds have properties different from their elements. • Compound (Honey Mustard for your chicken nuggets!!)

  3. Names and Formulas • All compounds have chemical names. • The chemical name tells scientists which elements come together to make the compound. • Why are lemons sour?

  4. Names and Formulas • Lemons are sour because they each contain a chemical called citric acid. • Citric acid is a weak organic acid found in citrus fruits like grapefruit, oranges, limes and lemons. • In its pure form citric acid is a white crystalline solid and is sour to taste like all food acids. It is sold as a food additive for cooking and can be found in most supermarkets. • The molecular formula of citric acid is C6H8O7

  5. What are chemical changes? • A chemical change occurs when a brand new substance is created, and is completely different from the original substance. • Rust is a chemical change!

  6. What are chemical changes? • The use of baking soda as a cleaning medium was created during the Statue of Liberty Renovation from 1984 - 1986. The statue was scheduled to be re-dedicated on July 4, 1986. They needed a cleaning process that would quickly clean the interior of the statue while not damaging the metal structure.

  7. Chemical Equations • http://www.brainpop.com/science/matterandchemistry/chemicalequations/ • A chemical equation is nothing more than a written expression of a chemical reaction that is to take place or that has already taken place. • Just like a Math Equation: The math symbol shows the work in answering the problem. The same thing happens in chemistry!

  8. The Law of Conservation of Mass • Law Of Conservation Of Mass states that- An amount of mass can be converted into equivalent amount of Energy or Work. Such as burning of fuel. • In Chemistry, it states that in a chemical reaction, the mass being produced and the mass of the reactant are equal. • (The saying, “you get out of it, what you put into it!”)

  9. Chemical Change • A chemical change refers to what happens to a chemical when an outside force or influence affects it. Some chemicals may breakdown when left in sunlight. Others may change states when heated or chilled. • When a molecular bond is broken down and forms a new bond, that is known as a chemical change. • RESULT: When a chemical change happens, new things are formed or changed entirely!

  10. Types of Chemical Change • Color change: Bleach removes the color from clothing and you end up with a material that has a different color to it. • So there is a change. • You get a new material that has different properties than the materials that you started with. • (The same happens when something RED goes through the wash, and all the whites are now PINK!)

  11. Color change

  12. Types of Chemical Change • Tarnish:is a combination of chemicals that have reacted with the metal as a result of being exposed to the air. • Compare one side of the pan to the other. Tarnish!

  13. Types of Chemical Change • Release of Gas: What happens when you add Mentos to soda? • Chemical reaction, and a chemical change as the Mentos dissolves and a gas is released! • http://dsc.discovery.com/videos/mythbusters-strangest-myths/

  14. Types of Chemical Change • A precipitate is a solid formed from the chemical reaction or two solutions. • Soap scum is a white or gray filmy layer that covers the surfaces around our showers, bathtubs, and sinks. • Soap scum can be found on shower curtains, bathroom fixtures, bathtubs, shower doors, tiling, and more.

  15. Types of Chemical Change • Example of Precipitate. • Soap Scum!

  16. Types of Chemical Change • Release of energy: Heat: Burning wood is a classic chemical change. When wood burns it becomes ash. When it burns it produces heat. This heat is just a product of wood burning and indicates a chemical change. • Light: Glow sticks are very common in showing that light is an indicator of a chemical change. Among other things, light from fireworks and light from lightning bugs is also a product from a chemical change.

  17. Types of Chemical Change

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