Physical Science Ch09

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  • 1.
    • To View the presentation as a slideshow with effects
    • select “View” on the menu bar and click on “Slide Show.”
    • To advance through the presentation, click the right-arrow key or the space bar .
    • From the resources slide, click on any resource to see a presentation for that resource.
    • From the Chapter menu screen click on any lesson to go directly to that lesson’s presentation.
    • You may exit the slide show at any time by pressing the Esc key .
    How to Use This Presentation
  • 2. Resources Chapter Presentation Image Bank Math Focus Bellringers Standards Assessment Visual Concepts
  • 3. Table of Contents
    • Section 1 Forming New Substances
    • Section 2 Chemical Formulas and Equations
    Chapter 9 Chemical Reactions
  • 4. Bellringer
    • The formation of water from its elements may be represented as follows:
    • 2H 2 + O 2  2H 2 O
    • What elements are present in water? How many atoms of each element are shown in the reactants? How many atoms of each element are shown in the products?
    • The representation 2H 2 + O 2  2H 2 O is called a chemical equation. Why do you think that the numbers of atoms do not change? Write your answers in your Science Journal.
    Section 1 Forming New Substances Chapter 9
  • 5. What You Will Learn
    • Four signs that indicate that a chemical reaction may be taking place are a change in color, the formation of a gas, the formation of a precipitate, and a change in energy.
    • Chemical reactions produce new substances whose chemical and physical properties differ from the properties of the original substances.
    • In a chemical reaction, chemical bonds break and atoms rearrange.
    • Chemical reactions absorb or release energy.
    Chapter 9 Section 1 Forming New Substances
  • 6. Combining Atoms Through Chemical Bonding
    • Chemical bonding is the joining of atoms to form new substances.
    • An interaction that holds two atoms together is called a chemical bond.
    • When chemical bonds form when electrons are shared ( covalent and metallic bonds ),
    • or when electrons are gained, or lost ( ionic bonds ).
    Section 1 Electrons and Chemical Bonding Chapter 8
  • 7. Chemical Reactions
    • A chemical reaction is a process in which one or more substances change to make one or more new substances.
    • The chemical and physical properties of the new substances that form in a chemical reaction differ from those of the original substances.
    Chapter 9 Section 1 Forming New Substances
  • 8. Chemical Reactions , continued
    • Signs that indicate a chemical reaction may be taking place are a color change, formation of a gas or a solid, and the release or absorption of energy.
    • A solid that is produced as a result of a chemical reaction in solution is called a precipitate.
    Chapter 9 Section 1 Forming New Substances
  • 9. Precipitate Chemical Reactions Chapter 9
  • 10. Chemical Reactions , continued
    • Even though the signs that indicate a chemical reaction is taking place are good signals of chemical reactions, they do not always guarantee that a reaction is happening.
    • The most important sign that a chemical reaction has taken place is the formation of new substances that have new properties.
    Chapter 9 Section 1 Forming New Substances
  • 11. Bonds: Holding Molecules Together
    • A chemical bond is a force that holds two atoms together in a molecule.
    • For a chemical reaction to take place, the chemical bonds in the starting substances must break. The atoms then rearrange, and new bonds form to make new substances.
    Chapter 9 Section 1 Forming New Substances
  • 12. Chemical Reactions Chapter 9
  • 13. Reactions and Energy
    • Energy is needed to break chemical bonds in the starting substances. (atoms bump into each other with enough force to break the bond).
    • As new bonds form in the final substances, energy is released.
    • A chemical reaction in which energy is released is called an exothermic reaction. Exothermic reactions can give off energy in several forms.
    Chapter 9 Section 1 Forming New Substances
  • 14. Reactions and Energy , continued
    • A chemical reaction in which energy is taken in is called an endothermic reaction.
    • The energy taken in during an endothermic reaction is absorbed from the surroundings.
    • Photosynthesis is an example of an endothermic process.
    Chapter 9 Section 1 Forming New Substances
  • 15. Reactions and Energy , continued
    • Neither mass nor energy can be created or destroyed in chemical reactions.
    • The law of conservation of energy states that energy cannot be created or destroyed but can change from one form to another.
    Chapter 9 Section 1 Forming New Substances
  • 16. Law of Conservation of Energy Chemical Reactions Chapter 9
  • 17. Bellringer
    • Look at the following formulas for chemical compounds, and identify the elements in each formula.
    • NaCl KBr C 12 H 22 O 11
    • NH 3 SiF 4 Fe(NO 3 ) 3
    • H 2 O 2 MgSO 4
    • What is the name and symbol of each element? How many atom of each element are present in each compound?
    • Write your answers in your Science Journal.
    Section 2 Chemical Formulas and Equations Chapter 9
  • 18. What You Will Learn
    • Chemical formulas are a simple way to describe which elements are in a chemical substance.
    • Chemical equations are a concise way to write how atoms are rearranged in a chemical reaction.
    • A balanced chemical equation shows the law of conservation of mass.
    Section 2 Chemical Formulas and Equations Chapter 9
  • 19. Chemical Formulas
    • A chemical formula is a combination of chemical symbols and numbers to represent a substance.
    • A chemical formula shows how many atoms of each kind of element are present in a molecule .
    • Examples: NaCl, H 2 O, NH 3
    Section 2 Chemical Formulas and Equations Chapter 9
  • 20. Chemical Formulas , continued
  • 21. Chemical Reactions Chapter 9
  • 22. Chemical Equations
    • A chemical equation uses chemical formulas, chemical symbols, and coefficients to describe a reaction.
    • Example: C + O 2  CO 2
    • Reactants. The starting materials in a chemical reaction
    • Products. The substances formed from a reaction
    Section 2 Chemical Formulas and Equations Chapter 9
  • 23. Chemical Equations , continued
    • A chemical equation that has a wrong chemical symbol or formula will not describe the reaction correctly.
    • The total number of atoms of each element in the reactants must equal the total number of atoms of that element in the products .
    • This process is called balancing the equation.
    Section 2 Chemical Formulas and Equations Chapter 9
  • 24. Chemical Equation Chemical Reactions Chapter 9
  • 25. Chemical Equations , continued
    • The law of conservation of mass states that mass cannot be created or destroyed in ordinary chemical and physical changes.
    • This law means that the total mass of the reactants is the same as the total mass of the products.
    Section 2 Chemical Formulas and Equations Chapter 9
  • 26. Law of Conservation of Mass Chemical Reactions Chapter 9
  • 27. Chemical Equations , continued
    • A coefficient is a number that is placed in front of a chemical symbol or formula.
    Section 2 Chemical Formulas and Equations Chapter 9
  • 28. Chemical Equations , continued
    • To balance an equation, change the coefficients—not the subscripts.
    • Changing the subscripts in the formula of a compound changes the compound.
    Section 2 Chemical Formulas and Equations Chapter 9
  • 29. Chemical Equations , continued
  • 30. Balancing Chemical Equations
    • 1. Count the atoms of each element in the reactants and in the products.
    • If the number of atoms of each element do not match, the equation must be balanced
  • 31. Balancing Chemical Equations
  • 32. Balancing Chemical Equations
    • 2. Place the needed coefficient in front of the molecule so that it gives the same amount of atoms in the reactants and products.
    • 3. Recount the atoms to check if the equation is balanced. If it is not continue to add coefficients and keep counting until the equation is balanced.
  • 33. Balancing Chemical Equations
  • 34. Balancing Chemical Equations
  • 35. Balancing Chemical Equations
    • Try to balance the chemical equations below:
    • Na + O 2    Na 2 O
    • N 2  + H 2    NH 2
    • Mg + HCl  MgCl 2 + H 2
  • 36. Answers:
    • Check your answers:
    • 4 Na + O 2    2 Na 2 O
    • N 2  + 2 H 2    2 NH 2
    • Mg + 2 HCl  MgCl 2 + H 2
  • 37. Concept Map Chapter 9 Chemical Reactions Use the terms below to complete the concept map on the next slide. products reactants chemical equations coefficients chemical reactions chemical formulas
  • 38. Chemical Reactions Chapter 9 Concept Map
  • 39. Chemical Reactions Chapter 9 Concept Map
  • 40. End of Chapter 9 Show Chemical Reactions Chapter 9
  • 41.
    • 1. In the sentence “She wrote a chemical formula that showed the parts of the compound,” what does the word compound mean?
      • A. a group of buildings set off and enclosed by a barrier
      • B. a word that consists of two or more elements or parts
      • C. a substance made up of two or more elements that are joined by chemical bonds
      • D. a leaf whose blade is divided into at least two leaflets
    Chapter 9 Standards Assessment
  • 42.
    • 1. In the sentence “She wrote a chemical formula that showed the parts of the compound,” what does the word compound mean?
      • A. a group of buildings set off and enclosed by a barrier
      • B. a word that consists of two or more elements or parts
      • C. a substance made up of two or more elements that are joined by chemical bonds
      • D. a leaf whose blade is divided into at least two leaflets
    Chapter 9 Standards Assessment
  • 43.
    • 2. Choose the appropriate form of the word react for the following sentence: “When an atom has one electron in its outer energy level, it _____easily with other atoms.”
      • A. reacting
      • B. reactive
      • C. reaction
      • D. reacts
    Chapter 9 Standards Assessment
  • 44.
    • 2. Choose the appropriate form of the word react for the following sentence: “When an atom has one electron in its outer energy level, it _____easily with other atoms.”
      • A. reacting
      • B. reactive
      • C. reaction
      • D. reacts
    Chapter 9 Standards Assessment
  • 45.
    • 3. Which of the following phrases means “a process that changes a substance into another substance”?
      • A. chemical reaction
      • B. physical process
      • C. atomic structure
      • D. buoyant force
    Chapter 9 Standards Assessment
  • 46.
    • 3. Which of the following phrases means “a process that changes a substance into another substance”?
      • A. chemical reaction
      • B. physical process
      • C. atomic structure
      • D. buoyant force
    Chapter 9 Standards Assessment
  • 47.
    • 4. Which of the following words or phrases is the closest in meaning to the word identify ?
      • A. observe
      • B. pick out
      • C. acquire
      • D. ask
    Chapter 9 Standards Assessment
  • 48.
    • 4. Which of the following words or phrases is the closest in meaning to the word identify ?
      • A. observe
      • B. pick out
      • C. acquire
      • D. ask
    Chapter 9 Standards Assessment
  • 49.
    • Use the diagram below to answer the next question.
    Chapter 9 Standards Assessment
  • 50.
    • 5. The model above shows the reaction of hydrogen and chlorine. Which of the following best describes the result of the reaction shown in the model?
      • A. Four new diatomic molecules form.
      • B. Bonds are formed between two hydrogen atoms.
      • C. The properties of the new molecules are the same as those of the original molecules.
      • D. Two molecules of a new compound are formed.
    Chapter 9 Standards Assessment
  • 51.
    • 5. The model above shows the reaction of hydrogen and chlorine. Which of the following best describes the result of the reaction shown in the model?
      • A. Four new diatomic molecules form.
      • B. Bonds are formed between two hydrogen atoms.
      • C. The properties of the new molecules are the same as those of the original molecules.
      • D. Two molecules of a new compound are formed.
    Chapter 9 Standards Assessment
  • 52.
    • 6. Which of the following contains one oxygen atom?
      • A. H 2 O
      • B. CO 2
      • C. 2N 2 O
      • D. Co
    Chapter 9 Standards Assessment
  • 53.
    • 6. Which of the following contains one oxygen atom?
      • A. H 2 O
      • B. CO 2
      • C. 2N 2 O
      • D. Co
    Chapter 9 Standards Assessment
  • 54.
    • 7. Atoms are never lost or gained during a chemical reaction. They are just
      • A. rearranged.
      • B. changed into other atoms.
      • C. corrected.
      • D. converted.
    Chapter 9 Standards Assessment
  • 55.
    • 7. Atoms are never lost or gained during a chemical reaction. They are just
      • A. rearranged.
      • B. changed into other atoms.
      • C. corrected.
      • D. converted.
    Chapter 9 Standards Assessment
  • 56.
    • 8. Which chemical equation correctly shows the formation of water from hydrogen and oxygen?
      • A. H 2 + O 2  H 2 O
      • B. 2H 2 + O 2  2H 2 O
      • C. H 2 + 2O  H 2 O
      • D. H + O 2  H 2 O
    Chapter 9 Standards Assessment
  • 57.
    • 8. Which chemical equation correctly shows the formation of water from hydrogen and oxygen?
      • A. H 2 + O 2  H 2 O
      • B. 2H 2 + O 2  2H 2 O
      • C. H 2 + 2O  H 2 O
      • D. H + O 2  H 2 O
    Chapter 9 Standards Assessment
  • 58.
    • 9. According to the periodic table, what is the chemical makeup of the compound MgCl 2 ?
      • A. the elements manganese and chromium
      • B. the elements mendelevium and chlorine
      • C. the elements magnesium and chlorine
      • D. the elements molybdenum and carbon
    Chapter 9 Standards Assessment
  • 59.
    • 9. According to the periodic table, what is the chemical makeup of the compound MgCl 2 ?
      • A. the elements manganese and chromium
      • B. the elements mendelevium and chlorine
      • C. the elements magnesium and chlorine
      • D. the elements molybdenum and carbon
    Chapter 9 Standards Assessment
  • 60.
    • 10. Use the periodic table to locate the elements Na and Cl. What type of compound is created when these two elements react?
      • A. isotopic
      • B. covalent
      • C. ionic
      • D. metallic
    Chapter 9 Standards Assessment
  • 61.
    • 10. Use the periodic table to locate the elements Na and Cl. What type of compound is created when these two elements react?
      • A. isotopic
      • B. covalent
      • C. ionic
      • D. metallic
    Chapter 9 Standards Assessment
  • 62.
    • 11. Ammonium sulfate has the chemical formula (NH 4 ) 2 SO 4 . How many atoms does one unit of ammonium sulfate contain?
      • A. 4
      • B. 7
      • C. 9
      • D. 15
    Chapter 9 Standards Assessment
  • 63.
    • 11. Ammonium sulfate has the chemical formula (NH 4 ) 2 SO 4 . How many atoms does one unit of ammonium sulfate contain?
      • A. 4
      • B. 7
      • C. 9
      • D. 15
    Chapter 9 Standards Assessment
  • 64.
    • 12. Chemical reactions are endothermic or exothermic. Which of the following is an example of an endothermic reaction?
      • A. Ice absorbs energy and melts to form liquid water.
      • B. Wood burns and releases light and heat.
      • C. Fireworks explode and release light.
      • D. Water absorbs energy and decomposes to form hydrogen and oxygen.
    Chapter 9 Standards Assessment
  • 65.
    • 12. Chemical reactions are endothermic or exothermic. Which of the following is an example of an endothermic reaction?
      • A. Ice absorbs energy and melts to form liquid water.
      • B. Wood burns and releases light and heat.
      • C. Fireworks explode and release light.
      • D. Water absorbs energy and decomposes to form hydrogen and oxygen.
    Chapter 9 Standards Assessment
  • 66.
    • 13. According to the periodic table, what is the atomic number of zinc, Zn?
      • A. 2.018
      • B. 30
      • C. 65.4
      • D. 19,620
    Chapter 9 Standards Assessment
  • 67.
    • 13. According to the periodic table, what is the atomic number of zinc, Zn?
      • A. 2.018
      • B. 30
      • C. 65.4
      • D. 19,620
    Chapter 9 Standards Assessment
  • 68.
    • 14. A cake is an example of a
      • A. solution.
      • B. compound.
      • C. mixture.
      • D. nonmetal.
    Chapter 9 Standards Assessment
  • 69.
    • 14. A cake is an example of a
      • A. solution.
      • B. compound.
      • C. mixture.
      • D. nonmetal.
    Chapter 9 Standards Assessment
  • 70.
    • Use the diagram below to answer the next question.
    Chapter 9 Standards Assessment
  • 71.
    • 15. Which of the following best describes the liquids in the graduated cylinder?
      • A. Of the six liquids, corn oil is the least dense.
      • B. The density of the liquids increases from maple syrup to corn oil.
      • C. The density of the top layers holds down less-dense liquids.
      • D. Of the six liquids, maple syrup is the least dense.
    Chapter 9 Standards Assessment
  • 72.
    • 15. Which of the following best describes the liquids in the graduated cylinder?
      • A. Of the six liquids, corn oil is the least dense.
      • B. The density of the liquids increases from maple syrup to corn oil.
      • C. The density of the top layers holds down less-dense liquids.
      • D. Of the six liquids, maple syrup is the least dense.
    Chapter 9 Standards Assessment
  • 73. Chapter 9