Types of Chemical Reactions Key

Types of Chemical Reactions Key Types of Chemical Reactions Do atoms rearrange in predictable patterns during chemical reactions? Why? Recognizing patterns allows us to predict future behavior. Weather experts use patterns to predict dangerous storms so people can get their families to safety. Political analysts use patterns to predict election outcomes. Similarly, chemists classify chemical equations according to their patterns to help predict products of unknown but similar chemical reactions. Model 1 – Types of Reactions Set A - Synthesis Set B - Decomposition 4Fe(s) + 3O2(g) ? 2Fe2O3(s) N2(g) + 3H2(g) ? 2NH3(g) 2SO2(g) + O2(g) ? 2SO3(g) MgCO3(s) ? MgO(s) + CO2(g) 8Li2S(s) ? 16Li(s) + S8(s) 2H2O(l) ? 2H2(g) + O2(g) MgO(s)+ H2O(l) ? Mg(OH)2(aq) 2KClO3(s) ? 2KCl(s) + 3O2(g) P2O5(g) + 3H2O(l) ? 2H3PO4(aq) 2Na2O2(s) ? 2Na2O(s) + O2(g) SO3(g) + H2O(l) ? H2SO4(aq) (NH4)2CO3(s) ? 2NH3(g) + H2O(l) + CO2(g) Set C - Single Replacement Set D - Double Replacement 2FeCl3(aq) + 3Zn(s) ? 2Fe(s) + 3ZnCl2(aq) AgNO3(aq) + NaCl(aq) ? AgCl(s) + NaNO3(aq) 2Al(NO3)3(aq) + 3Ca(s) ? 3Ca(NO3)2(aq) + 2Al(s) 2HNO3(aq) + Mg(OH)2(aq) ?Mg(NO3)2(aq) + 2H2O(l) Mg(s) + CuSO4(aq) ? MgSO4(aq) + Cu(s) FeBr3(aq) + K3PO4(aq) ? FePO4(s) + 3KBr(aq) 2Al(s) + 6HCl(aq) ? 2AlCl3(aq) + 3H2(g) Na2CO3(aq) + CaCl2(aq) ?CaCO3(s) + 2NaCl(aq) Cl2(g) + 2NaBr(aq) ? 2NaCl(aq) + Br2(l) FeS(s) + 2HCl(aq) ? H S(g) + FeCl (aq) ZnBr2(aq) + F2(g) ? ZnF2(aq) + Br2(l) HCl(aq) + NaOH(aq) ? H O(l) + NaCl(aq) 1. The chemical equations in Model 1 contain the phase notations (s), (l), (g), and (aq). Write each symbol by each meaning. dissolved in water liquid solid gas (aq) (l) (s) (g) 2. Based on the examples provided, which set(s) of reactions in Model 1 typically involve ions in solution (A, B, C or D)? C, D 3. Based on the examples provided, which set(s) of reactions in Model 1 typically involve gases and/or solids? A, B 4. Match each description below to one of the reactions sets (A, B, C or D) from Model 1. _____D_____ Ionic compounds dissolved in water switch partners. _____B_____ One compound breaks into elements or smaller compounds. _____A_____ Two or more elements or compounds combine to form one product. _____C_____ Part of an ionic compound is removed and replaced by a new 5. Define the following terms as they are commonly used in the English language. Synthesis— put together Decomposition— break down Single Replacement— one replaces another Double Replacement— two switch Combustion— burn 6. The four sets of chemical reactions shown in Model 1 have the following general names. Discuss within your group which name belongs to which set of chemical reactions. Write the name in the appropriate place in Model 1. Single Replacement Reaction C Synthesis Reaction A Double Replacement Reaction D Decomposition Reaction B 7. Can two elements be used as reactants for a synthesis reactions? If yes, give at least one example from Model 1 to support your answer. Yes, 4Fe(s) + 3O2(g) ? 2Fe2O3(s) 8. Can two compounds be used as reactants for a synthesis reaction? If yes, give at least one example from Model 1 to support your answer. Yes, P2O5(g) + 3H2O(l) ? 2H3PO4(aq) 9. What types of substances (elements or compounds) are seen in the products of decomposition reactions? Use examples from Model 1 to support your answer. Both elements and compounds can be seen in the products. MgCO3(s) ? MgO(s) + CO2(g) and 8Li2S(s) ? 16Li(s) + S8(s) 10. In single replacement reactions, do any of the atoms change their charge? If yes, use an example from Model 1 to describe the changes that take place. Yes, 2FeCl3(aq) + 3Zn(s) ? 2Fe(s) + 3ZnCl2(aq) Iron changes from +3 to 0 and Zinc changes from 0 to +2 11. In double replacement reactions, do any of the atoms change their charge? If yes, use an example from Model 1 to describe the changes that take place. No 12. Choose one example from the set of synthesis reactions in Model 1. 2NH3(g) ? N2(g) + 3H2(g) Decomposition 13. Identify each of the reactions below as synthesis (S), decomposition (D), single replacement (SR) or double replacement (DR). ____S_________ K2O(s) + H2O(l) ? 2KOH(aq) ____DR________ 2MgCl2(aq) + Na2CO3(aq) ? 2NaCl(aq) + MgCO3(s) ____D_________ 2Al2O3(s) ? 4Al(s) + 3O2(g) ____SR________ Cu(NO3)2(aq) + Zn(s) ? Cu(s) + Zn(NO3)2(aq) ____DR________ H2SO4(aq) + 2NaOH(aq) ? Na2SO4(aq) + 2H2O(l) ____SR________ 2K(s) + 2H2O(l) ? 2KOH(aq) + H2(g) ____S_________ 2O2(g) + N2(g) ? N2O4(g) ____D_________ 2NaF(s) ? 2Na(s) + F2(g) 14. A student writes the following incorrect chemical equation for the synthesis of magnesium Oxide. Mg + O2 ? MgO2 Another student writes the following incorrect synthesis reaction. Mg + O ? MgO 2Mg + O2 ? 2MgO 15. A student writes the following incorrect chemical equation for a single replacement reaction between lithium bromide and fluorine. 2LiBr(aq) + F2(g) ? 2Li(s) + 2FBr(g) 2LiBr(aq) + F2(g) ? Br2(g) + 2LiF(aq) 16. A student writes the following incorrect chemical equation for a double replacement reaction between iron(III) bromide and sodium hydroxide solutions. FeBr3(aq) + NaOH(aq) ? FeOH(s) + NaBr3(aq) FeBr3(aq) + 3NaOH(aq) ? Fe(OH)3(s) + 3NaBr(aq) 17. Consider the following chemical reaction written as a word equation. diphosphorus pentoxide + water ? phosphoric acid Read This! Chemists use their knowledge of synthesis, decomposition, single replacement, and double replacement to predict what will happen in chemical reactions. When predicting the products for a reaction it is important to remember that atoms or ions will only combine in ways that make them stable, otherwise the reaction will not happen under normal conditions. This means that it is important to pay attention to ion charges, the natural state of elements, and the formulas of common molecular substances like carbon dioxide and water. It is only after predicting the products and writing the correct formulas that a chemist would then apply the law of conservation of mass and balance the chemical equation using coefficients as needed. 18. Use your understanding of common chemical reactions to predict the products for the following reactions. Writing a word equation may be helpful. Balance the chemical equations after you have written the correct chemical formulas for all of the reactants and products. a. 4Al(s) + 3N2(g) ? 2Al2N3 (s) b. 2dinitrogen oxide(g) ? 2N2(g) + O2(g) c. SrCl2(aq) + 2AgNO3(aq) ? 2AgCl(s) + Sr(NO3)2(aq) d. 2chromium(III) nitrate(aq) + 3zinc chloride(aq) ?3Zn(NO3)2 (aq) + 2CrCl3 (s) e. 2Na(s) + Cl2(g) ? 2NaCl(s) f. Zn(s) + 2HCl(aq) ? ZnCl2 + H2 Extension Questions Model 2 – Combustion Reactions 2C8H18(g) + 25O2(g) ? 16CO2(g) + 18H2O(g) (C8H18 = octane—gasoline component) 2C4H10(g) + 13O2(g) ? 8CO2(g) + 10H2O(g) (C4H10 = butane—lighter fuel) CH4(g) + 2O2(g) ? CO2(g) + 2H2O(g) (CH4 = methane—natural gas) 19. What are the products in all of the combustion reactions in Model 2? CO2(g) + H2O(g) 20. What reactant is common in all of the combustion reactions in Model 2? Hydrocarbon + O2(g) 21. The “fuel” in most combustion reactions is a hydrocarbon. Using the examples in Model 2, write a description for the classification of substances known as hydrocarbons. Hydrocarbons contain C and H and sometimes O 22. Predict the products of the following combustion reactions, and balance each reaction equation. 23. Compounds such as isopropyl alcohol (C3H7OH) and glucose (C6H12O6) can also undergo combustion in a similar way. Predict the products of the following combustion reactions, and balance each reaction equation. 24. For each of the reaction types in Model 1, explain why a combustion reaction CANNOT be classified as that type. Use a complete sentence in each answer. All combustion reactions contain a hydrocarbon combining with oxygen producing water and carbon dioxide.