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Chapter 8 Chemical equations & Reactions. Finding (Counting) the numbers of atoms or moles of atoms in a compound (NH 4 ) 2 SO 4 N= S= H= O= Total Number of atoms=.
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Chapter 8Chemical equations & Reactions Finding (Counting) the numbers of atoms or moles of atoms in a compound (NH4)2SO4 N= S= H= O= Total Number of atoms=
Now put a Coefficient in front of that compound4(NH4)2SO4 N= S= H= O= Total Number of atoms=Mg3(PO4)2 Mg= P= O=3Mg3(PO4)2 Mg= P= O=
Hydrates can be Troublesome!CuSO4*5H2O4 CuSO4*5H2O6CaCl2*5H2O
I. Chemical Equations: show the chemical formulas and the amounts of reactants & products. Show phases in chemical rxn! s,l,g,aq preciptate
Law of Conservation of Matter, Mass, Energy and Charge all apply to chemical equations. None are created nor destroyed, just rearrangedReactants=Products Review endo A + B + Energy C exo A + B C + energy B. coefficients”# in front of formula that tells the #of molecules, moles, atoms or formula units(ionic) taking part in rxn. Ex: 2H2 + O2 2H2O sum of coefficients= ___molecules(moles) of hydrogen and ___molecules(moles) of oxygen yield/makes___molecules(moles) of water
II. A Is the equation Balanced? Yes or Norules: 1. List all atoms 2. Count atoms on both the reactant and product side Ex: 2Na + 2H2O 2NaOH + H2
B. Writing chemical Equations from word equations1. Write formulae(remember diatomics)2.Determine coefficients to balance equationsHint: Table K /L for acids and bases Chlorine + Sodium Bromide Bromine + Sodium Chloride
Aluminum sulfate + calcium chloride aluminum chloride + calcium sulfate
1A. 5NH3 N=5 H=15 B. Ca(OH)2 Ca=1 O=2 H=2 C. 3BaSO4*5H2O Ba=3 S=3 O= 12 + 15 =27 H=30 D. 6Na(C2H3)4 Na=6 C=48 H=72 2. Silicon tetrachloride(g) + magnesium(s) silicon(s)+ magnesium chloride (s) 3A Yes Zn + 2HCl ZnCl2 + H2
B. No H2SO4 + 2NaOH H2O + Na2SO4 c. No Pb(NO3)2+ 2NaI PbI2 + NaNO3 D. No Na + O2 Na2O E. No Cu + S Cu2S F. Yes CuO + H2 Cu + H2O G. Yes Ba(OH)2 + CO2 BaCO3 + H2O
1a Ok Zn + H2SO4 ZnSO4 + H2 b. 2K + Br2 2KBr c. 2 H2O O2 +2 H2 d. Cl2 + 2KI 2KCl + I2 e. Ok HNO3 + LiOH H2O + LiNO3 • 2 N2 + O2 2 N2O • Ok NH4Cl + NaOH NH4OH + NaCl
2a Na(s) + I2(S) NaI(s) 2Na(s) + I2(S)2 NaI(s) B. Zn(s) + HBr(aq) ZnBr2(s) + H2(g) Zn(s) + 2HBr(aq) ZnBr2(s) + H2(g) C. KOH(s) K2O(s) + H2O(l) 2KOH(s) K2O(s) + H2O(l)
D Mg(s) + H2O(l) Mg(OH)2(aq) + H2(g) Mg(s) + 2H2O(l) Mg(OH)2(aq) + H2(g)
pg3 1.A Ca + O2 CaO 1B. 2Ca + O2 2 CaO 2A H2O H2 + O2 2B 2 H2O 2H2 + O2 3A. Br2 + NaCl NaBr + Cl2 3B Br2 + 2NaCl 2NaBr + Cl2 4A. Mg + FeCl3 MgCl2 + Fe 4B. 3Mg + 2FeCl3 3 MgCl2 + 2Fe
5A. KOH + AlI3 KI + Al(OH)3 5B 3 KOH + AlI3 3KI + Al(OH)3 6A. FeCl2 + BaSO4 FeSO4 + BaCl2 6B. FeCl2 + BaSO4 FeSO4 + BaCl2 7A. Al2S3 + LiNO3 Al(NO3)3 + Li2S 7B Al2S3 + 6LiNO3 2 Al(NO3)3 +3 Li2S
III. Types of Reactions • Synthesis (Direct Combination)- put together Ex. A+B C Element + Element Compound C + E C
B. Decomposition (Analysis)- to break apart( Most require a catalyst (speeds up the rate of rxn without being altered or changed) • Name 3 catalysts • . Heat • Electricity • Chemicals • Catalyst can be placed above arrow • Ex ABA+B C E +E
p. 27822a sodium + oxygen sodium oxide 4Na + O2 2Na2O22b. Magnesium + fluorine magnesium fluoride Mg + F2 MgF2
23A. 2HgO 2Hg + O223B 2 H2O 2H2 + O223C 2Ag2O 4Ag + O223D. CuCl2 Cu + Cl2
38 A potassium + chlorine potassium chloride 2K + Cl2 2KCl38B hydrogen + iodine hydrogen iodide H2 + I2 2HI38C magnesium + oxygen magnesium oxide 2Mg + O2 2MgO
C. Single Replacement-one element switches or cuts in Ex. Metals (cations) C + AB CB + A m only replace m Nonmetals(anions) C + AB AC + B nm only replace nm E + C E + C
Will SR occur? Use Table Jelement that is coming in must be higher on the chart than element in compound Cr + FeSO4 Zn + AgNO3
Cl2 + NaF F2 + NaI--->
D. Double Replacement -2 elements switch or cut in What drives DR? Must form water, gas ppt(s ) AB + CD AD + CB C + C C + C Ex. AgNO3 + NaCl AgCl + NaNO3
p. 27935a Ni + CuCl2 NiCl2 + Cu35b Zn + Pb(NO3)2 Zn(NO3)2 + Pb35c. Cl2 + 2KI 2KCl + I235d no rxn35e Ba + 2H2O H2 + Ba(OH)2
p. 27825a AgNO3 + NaCl NaNO3 + AgCl25b. Mg(NO3)2 + 2KOH Mg(OH)2 + 2KNO325c 3LiOH + Fe(NO3)3 3LiNO3 + Fe(OH)3
IV. Missing Reactant or product • List atoms 2. Find what is not equal Ex: 2Na + 2H2O X + 2NaOH
V. Determine Missing Mass Law of Conservation of Mass: Total mass of reactants = total mass of products Ex#1 If 103.0g of potassium chlorate are decomposed to form 62.7g of potassium chloride and oxygen gas according to the equation, how many grams of oxygen are formed? 2KClO3 2KCl + 3O2
Ex#2 Reactant (s) Product(s)Magnesium + Oxygen Magnesium Oxide ? g + 16.0g 40.3gBased on the Law of Conservation of Mass predict the minimum amount of magnesium that will react with 16.0g of oxygen to produce 40.3 g of magnesium oxide.
Ex#3Reactant(s) Product(s)Magnesium + Oxygen Magnesium Oxide 12.2g + 8.0g ?gAssuming that magnesium and oxygen will react completely with one another, predict the mass of magnesium oxide that will be produced.
Ex#4 Reactant(s) Product(s)Magnesium + Oxygen Magnesium Oxide + Oxygen 48.6g + 50.0g 80.6g + ?gPredict the mass of oxygen that will be left over after the reaction of 48.6 grams of magnesium with 50.0 g of oxygen