<p>Name ______Per. ______</p><p>Ch 7 Study Guide - Chemical Reactions</p><p>1. Answer questions about chemical reactions a. What three things can indicate a chemical change occurred?</p><p> b. What is the general name of the substance(s) that change(s) during a reaction?</p><p> c. What happens to atoms during a chemical reaction?</p><p> d. Which is the general name of the substance(s) that results from a reaction?</p><p> e. Where in molecules is chemical energy stored?</p><p>2. Choose between Endothermic VS Exothermic reactions</p><p> a. releases energy into the surroundings - </p><p> b. absorbs energy from surroundings -</p><p> c. stores energy in bonds -</p><p> d. usually results in light or heat -</p><p> e. changes light energy into plants –</p><p>3. Choose between S- Synthesis, D- Decomposition, SR- Single Replacement, DR- Double Replacement, or C- Combustion Reactions a. Methane burns with oxygen - </p><p> b. Has 2 compounds on either side -</p><p> c. Photosynthesis -</p><p> d. 1 element is oxidized, 1 element is reduced -</p><p> e. Digestion - </p><p> f. Breaks into at least two products - </p><p> g. Makes a larger, more complex compound - </p><p> h. Results in carbon dioxide and water - </p><p> i. Using electrolysis to make H2 and O2 gases - </p><p> j. Making sodium chloride (NaCl) - k. Has a single element on either side – </p><p>4. Answer the questions about balancing reactions a. Which numbers can you change? Subscripts or Coefficients</p><p> b. What is the Law of Conservation of Matter?</p><p> c. Why do reactions need to be balanced?</p><p> d. If the reaction is balanced, the mass of the reactions equals the mass of the ______.</p><p> e. Explain the Law of Definite Proportions.</p><p> f. How do you know when a reaction is in equilibrium?</p><p> g. Balance the following reactions and identify the type of reaction. Type</p><p>____ K3PO4 + ____ HCl  ____ KCl + ____ H3PO4 ______</p><p>____ KClO3  ____ KCl + ____ O2 ______</p><p>____ Na +____ I2  ____ NaI ______</p><p>____ C3H8 + ____ O2  ____ CO2 + ____ H2O ______</p><p>____ Zn + ____ HCl ---> ____ ZnCl2 + ____ H2 ______</p><p>5. Odds & Ends a. If a substance accepts electrons, is it oxidized or reduced?</p><p> b. Name 4 factors that can speed up chemical reactions 1. 2. 3. 4.</p><p> c. What would happen to foods if we didn’t have refrigeration and how does this relate to chemical reactions?</p>