9th Grade Chapter 7 Lesson 1


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9th Grade Chapter 7 Lesson 1

  1. 1. Pgs. 155-162 For Student Use Only 9 th Grade Chapter 7 Lesson 1
  2. 2. Question 1 What is a chemical reaction? <ul><li>A. Can results from molecules colliding with each other </li></ul><ul><li>C. Molecules can combine or break apart </li></ul><ul><li>B. Starts with chemical changes </li></ul><ul><li>D. A chemical change resulting from a collision between atoms or molecules </li></ul>
  3. 3. Key <ul><li>1) A,B,C,D </li></ul>
  4. 4. Chemistry is Everywhere <ul><li>Student generated ideas: </li></ul><ul><li>Explain which pictures could be showing a chemical reaction. Explain why you chose that picture. </li></ul><ul><li>Pic 2= because if you mix different chemicsls you can get different colors </li></ul><ul><li>Pic. 4: shows molecules combinig and breaking apart </li></ul><ul><li>Pic 5= fire is putting in enerrgy to create a reaction by helping milescules combine </li></ul>
  5. 5. Chemistry is Everywhere <ul><li>Chemical Reactions </li></ul><ul><ul><li>Original substances are changed into something different </li></ul></ul><ul><ul><li>Reactants= chemical substances that undergo changes </li></ul></ul><ul><ul><li>Products= things that are produced in the chemical reaction </li></ul></ul><ul><li>Reaction of sulfuric acid and sugar. The acid dehydrates the sugar forming a pillar of carbon (black) and steam. </li></ul>http://www.scienceclarified.com/images/uesc_09_img0486.jpg
  6. 6. Chemistry is Everywhere <ul><li>Student generated ideas: </li></ul><ul><li>Write any chemical equations you can think of with the help of the pictures over to the side. </li></ul>
  7. 7. Chemistry is Everywhere <ul><li>Chemical Equations: </li></ul><ul><li>The reactants are on the left side of the equation </li></ul><ul><li>The products are on the right side of the equation </li></ul><ul><ul><li>2H 2 + O 2 = 2H 2 O </li></ul></ul><ul><li>Coefficient tells how many molecules of the substance are in the reaction </li></ul><ul><li>Subscript tells how many atoms of molecules are present </li></ul>H 2 + Cl 2   -->   2 HCl http://www.personal.kent.edu/~cearley/ChemWrld/balance/balance.htm
  8. 8. Chemistry is Everywhere <ul><li>Student generated ideas: </li></ul><ul><li>What type of chemical reactions take place in baking a cake? </li></ul>
  9. 9. Chemistry is Everywhere <ul><li>Chemical Reactions: </li></ul><ul><li>Law of conservation of mass: </li></ul><ul><ul><li>The total mass of the reactants is equal to the total mass of the products </li></ul></ul><ul><ul><li>Atoms are conserved in chemical reactions and have to be balanced </li></ul></ul>http://www.winsite.com/info/images/1500000035527/methane.gif
  10. 10. Chemistry is Everywhere <ul><li>Student generated ideas: </li></ul><ul><li>How do you plan to balance equations? What do you need to know to balance equations? </li></ul>
  11. 11. Chemistry is Everywhere <ul><li>Balancing Chemical Equations: </li></ul><ul><li>RULES: </li></ul><ul><ul><li>1. Remember that only the coefficients on an equation NOT the molecular formulas may be adjusted </li></ul></ul><ul><ul><li>2. Balance the element with the largest subscript first </li></ul></ul><ul><ul><li>3. In an equation involving a pure element and one or more compounds balance the pure element last </li></ul></ul>http://www.winsite.com/info/images/1500000035527/methane.gif
  12. 12. Energy is everywhere <ul><li>List all the ways that chemistry will produce energy in the pictures to the side. </li></ul>
  13. 13. Chemistry is Everywhere <ul><li>Energy in Chemical Reactions: </li></ul><ul><li>Activation Energy: Energy put into the reaction to make the reaction happen </li></ul><ul><li>Exothermic reaction- releases energy </li></ul><ul><li>Endothermic reaction- produce energy </li></ul>
  14. 14. Chemistry is Everywhere <ul><li>Energy in Chemical Reactions: </li></ul><ul><li>2 nd law of thermodynamics states: </li></ul><ul><ul><li>Energy and matter always tend to head toward less usable energy and greater disorder (called entropy- amount of disorder or decay) </li></ul></ul><ul><ul><li>Also- in every physical and chemical reaction, some of the energy cannot be used again </li></ul></ul>
  15. 15. Energy is everywhere <ul><li>Based on the pictures what is one factor that affects reactions. </li></ul>
  16. 16. Chemistry is Everywhere <ul><li>Factors that affect chemical reactions: </li></ul><ul><li>Temperature: an increase in temperature will usually speed up a rxn (reaction) (due to more kinetic energy and colliding of particles) </li></ul><ul><li>Concentration: increased concentration increases the rate of rxn- (more particles to collide) </li></ul>
  17. 17. Chemistry is Everywhere <ul><li>Factors that affect chemical reactions: </li></ul><ul><li>Surface Area: the surface area of the of the reactants increases the speed of the reaction (more area for molecules to collide) </li></ul><ul><li>Catalysts: a substance that speeds up a reaction without being permanently changed (this lowers the amount of activation energy) </li></ul>