Transcript Slide 1
Synthesis – 1 product Decomposition – 1 reactant Single displacement – 1 element & 1 compound react to produce a different element & a different compound Double displacement – 2 compounds react to form two different compounds. Neutralization – acid and base in the reactants & water as one of the products. Combustion – O2 as a reactant & CO2 and H2O as the products. Does your reaction have two (or more) substances combining to form one compound? If yes, then it's a synthesis reaction. 2 H2(g) + O2(g) 2 H2O(l) Na(s) + Cl2(g) NaCl(s) Does your reaction have one compound breaking down to make two or more smaller substances? If yes, then it's a decomposition reaction. 2 HgO(l) 2 Hg(l) + O2(g) NaHCO3(s)Na2CO3(s)+ H2O(l) + CO2(g) Does your reaction start with a compound and an element and produce a different compound and a different element? If yes, then it's a single displacement reaction . CuCl2(aq) + Mg(s) MgCl2(aq) + Cu(s) KCl(aq) + F2(g) KF(aq) + Cl2(g) A double displacement reaction starts with two compounds and makes two new compounds. FeCl3(aq)+MgSO4(aq)Fe2(SO4)3(s)+MgCl2(aq) NaCl(aq) + AgNO3(aq) NaNO3(aq) + AgCl(s) Does your reaction have an acid as one of your reactants and water as one of the products? If yes, then it's an acid-base or neutralization reaction. HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) acid base Ca(OH)2(aq) + H3PO4(aq) H2O(l) + Ca3(PO4)2(aq) base acid Does your reaction have oxygen as one of it's reactants and carbon dioxide and water as products? If yes, then it's a combustion reaction. CH4(g) + O2(g) CO2(g) + H2O(g) C8H18(g) + O2(g) CO2(g) + H2O(g) To predict the products for any equation, you must first determine the type of reaction by looking at the reactants. Synthesis – 1 product Decomposition – 1 reactant Combustion – O2 as a reactant & CO2 and H2O as the products. 2 or more reactants and you’re told that there’s only one product = synthesis When writing the products, you must look at the charges of the ions. The equations will most likely not be balanced! Example: Al(s) + Br2(l) Example: Ca(s) + N2(g) 1 reactant = decomposition (if you have a decomposition, then it will be a compound splitting up into its elements) Remember the “7” diatomic molecules and to write them with a “2” if by themselves. Example: CCl4(l) Example: Mg3N2(s) hydrocarbon (compound with C & H) + O2 = combustion (always have CO2 and H2O as your products) Example: CH4(g) + O2(g) Example: C3H8O(g) + O2(g) C8H18 + O2 Ba(NO3)2 Mg + O2 Single displacement – 1 element & 1 compound react to produce a different element & a different compound Double displacement – 2 compounds react to form two different compounds. Neutralization – acid and base in the reactants & water as one of the products. 1 element & 1 compound = single displacement (replacement) In the products, you can’t have two positive ions or two negative ions combined together, only one positive and one negative ion. Example: Mg(s) + Zn(NO3)2(aq) Example: Cl2(g) + KF(aq) 2 ionic compounds = double displacement (replacement). As before, you can’t put two positive ions or two negative ions together. Example: AgNO3(aq) + NaCl(aq) Example: Fe2(SO4)3(aq)+ Na3PO4 (aq) 1 acid (starts with H) & 1 base (ends with OH) = acid-base or neutralization (always makes H2O as one product) Water gets rid of all hydrogen and hydroxide ions. The other compound comes from the leftover ions. Example: HCl(aq) + KOH(aq) Example: Ca(OH)2(aq)+ H2SO4(aq) If a substance is an aqueous solution (aq), it is a substance that dissolves in water, or is soluble in water. If a substance is insoluble, it will not dissolve in water, and when formed as the result of a reaction will appear as a precipitate (solid). If a substance is slightly soluble or partially soluble in water, only a small portion of that substance will dissolve in water. Electrolyte – solution that that has the ability to conduct electricity. When an ionic compound dissolves in water it separates into ions and is called a strong electrolyte, for example NaCl dissolved in water. Compounds that dissolve in water but do not conduct electricity are called nonelectrolytes, for example, sugar dissolving in water. In order for a compound to be an aqueous solution, one of the ions (either the positive ion or the negative ion) must be soluble in water, but not both Ca(NO3)2 CuOH CaCl2 (NH4)2SO4 Zn3(PO4)2 SrO FeCO3 In all precipitation reactions, the ions of one substance are exchanged with the ions of another substance when their aqueous solutions are mixed At least one of the products formed is insoluble in water KI(aq) + AgNO3(aq) KNO3(aq) + AgIs K+ Ag+ K+ Ag I- NO3- NO3- I Here is what we’ve already covered Determine what ions each aqueous reactant has Exchange Ions ◦ (+) ion from one reactant with (-) ion from other Balance Charges of combined ions to get formula of each product ° Determine Solubility of Each Product in Water ◦ solubility rules/table ◦ if any of the products are insoluble or slightly soluble, a precipitate will form ◦ If all substances formed are aqueous solutions then no precipitate will form and there is really no reaction, just ions floating around in water. Predict the products given each of the following reactants. Also denote which compound forms a precipitate: Cu(NO3)2(aq) + KOH(aq) FeCl3(aq) + Mg3(PO4)2(aq) NaBr(aq) + KNO3(aq) Equations which describe the chemicals in aqueous solution and their product molecules are called molecular equations KCl(aq) + AgNO3(aq) KNO3(aq) + AgCl(s) equations which describe the actual ions and molecules in the solutions as well as the molecules of solid, liquid and gas not dissolved are called ionic equations K+(aq)+Cl-(aq)+Ag+(aq)+NO3-(aq)K+(aq)+NO3-(aq)+AgCl(s) ions that are both reactants and products are called spectator ions K+(aq)+Cl-(aq)+Ag+(aq)+NO3-(aq)K+(aq) + NO3- (aq) + AgCl(s) an ionic equation in which the spectator ions are dropped is called a net ionic equation Cl- (aq) + Ag+ (aq) AgCl(s) Write the molecular, complete ionic and net ionic equations for the following equations. Also identify any spectator ions : Cu(NO3)2(aq) + KOH(aq) KNO3(aq) + Cu(OH)2(s) Write the molecular, complete ionic and net ionic equations for the following equations. Also identify any spectator ions : Fe2(SO4)3(aq)+Pb(ClO3)2(aq)Fe(ClO3)3(aq)+PbSO4(s) Write the molecular, complete ionic and net ionic equations for the following equations. Also identify any spectator ions : KCl(aq) + (NH4)2SO4(aq) K2SO4(aq) + NH4Cl(aq)