Transcript Ch 6 Review
Ch 6 Review Chemical Reactions What three things can indicate a chemical change occurred? • 1. • 2. • 3. • Where in molecules is chemical energy stored? • What happens to atoms during a chemical reaction? A + B AB • What is the general name of the substance(s) that change(s) during a reaction? • Which is the general name of the substance(s) that results from a reaction? AB + C AC + B Endothermic OR Exothermic? • releases energy into the surroundings ? • absorbs energy from surroundings ? • stores energy in bonds ? • usually results in light or heat ? • changes light energy into plants ? S, D, SR, DR, or C? 1. Methane burns with oxygen – 2. Has 2 compounds on either side – 3. Photosynthesis – 4. 1 element is oxidized, 1 element is reduced – 5. Digestion – 6. Breaks into at least two products - S, D, SR, DR, or C? 1.Makes a larger, more complex compound – 2.Results in carbon dioxide and water 3. Electrolysis to make H2 and O2 gases - 4.Making sodium chloride (NaCl) 5.Has a single element on either side – • Which numbers can you change to balance? Subscripts or Coefficients • Why do reactions need to be balanced? • If the reaction is balanced, the mass of the reactions equals the mass of the _____________. • What is the Law of Conservation of Matter? • Explain the Law of Definite Proportions. • How do you know when a reaction is in equilibrium? Balance the following reactions and identify the type of reaction. ____ K3PO4 + ____ HCl ____ KCl + ____ H3PO4 ____ KClO3 ____ KCl + ____ O2 ____ Na +____ I2 ____ NaI ____ C3H8 + ____ O2 ____ CO2 + ____ H2O ____ Zn + ____ HCl ---> ____ ZnCl2 + ____ H2 If a substance accepts electrons, is it oxidized or reduced? Zn was oxidized Went from neutral (0) to (+2) Cu Cl + Cl Zn Zn Cl + Cu Cl Cu was reduced Went from (+2) to Neutral (0) Name 4 factors that can speed up chemical reactions. 1. 2. 3. 4. What would happen to foods if we didn’t have refrigeration and how does this relate to chemical reactions?