1. Aim: Stoichiometry and Chemical Reactions Review

2. I. Parts of a Chemical Reaction and Balancing  What is a chemical reaction?  Example: HCl (aq) + Zn (s)  H 2 (g) + ZnCl 2 (aq) (NOT BALANCED) One or more substances are made into NEW substance(s) (bonds are broken and/or made) Reactants yields Products Physical state of substances

3. I. Parts of a Chemical Reaction and Balancing  Example: HCl (aq) + Zn (s)  H 2 (g) + ZnCl 2 (aq) (NOT BALANCED)  Problem:  The above chemical reaction breaks the Law of Conservation of Mass: Matter is neither created or destroyed in a chemical reaction So… the numbers of atoms must remain unchanged in a reaction

4. I. Parts of a Chemical Reaction and Balancing  Balancing Equations: Coefficients are used to balance the number of at atoms of each element on both sides of the reaction. Coefficients must be the smallest whole number that balance the reaction.  NOTE: Coefficients can be changed, HOWEVER, subscripts CANNOT!  Example:  ____ HCl (aq) + ____ Zn (s)  ____ H 2 (g) + ____ ZnCl 2 (aq) 21 1 1

5. I. Parts of a Chemical Reaction and Balancing  Examples: Balance the following chemical reactions 1._____ N 2 + _____ H 2  _____ NH 3 2. _____ Al 2 O 3  _____ Al + ____ O 2 1 3 2 2 43

6. I. Parts of a Chemical Reaction and Balancing  Examples: Balance the following chemical reactions 3._____ Al + _____ Br 2  _____ AlBr 3 4. _____ AlBr 3 + ___ Cl 2  _____ Al Cl 3 + ____ Br 2 232 2 32 3

7. II. Types of Reactions - Synthesis  What is it?  General Equation: ________________________________ When two or more reactants combine to form a single product A + B  AB

8. Checks for Understanding Magnesium ribbon is heated and reacts with oxygen in the air forming magnesium oxide 1.Balance the following chemical reaction ____ Mg (s) + ____ O 2 (g)  ____ MgO (s) 2 1 2

9. II. Types of Reactions - Synthesis C. Balancing: Balance the following synthesis reactions: 1. ____ S + ____ O 2  ____ SO 3 2.____ C + ____ H 2  ____ C 3 H 8 2 3 2 3 4 1

10. II. Types of Reactions - Synthesis C. Balancing: Balance the following synthesis reactions: 3. ____ P 4 + ____ O 2  ____ P 2 O 3 4. ____ CaO + ____ H 2 O  ____ Ca(OH) 2 3 2 1 1 1

11. II. Types of Reactions - Synthesis D. Chemical Reactions in Words: Write and balance the following equations. Remember to criss-cross and pay attention to diatomic elements (HONCLBrIF). Iron and oxygen yields iron (III) oxide ___ Fe+ ___ O 2  ___ Fe 2 O 3 43 2

12. III. Types of Reactions - Decomposition  What is it?  General Equation: ________________________________ Single compound is broken down (decomposed) into two or more simpler substances AB  A + B

13. Checks for Understanding Real World Example: (video)video Hydrogen peroxide decomposes into water and oxygen 1.Balance the following chemical reaction ____ H 2 O 2 (l)  ____ H 2 O (l) + ______ O 2 (g) 22 1

14. III. Types of Reactions - Decomposition C. Balancing: Balance the following synthesis reactions: 1. ____ HgO  ____ Hg + ____ O 2 2.____ AgCl  ____ Ag + ____ Cl 2 22 1 2 2 1

15. III. Types of Reactions - Decomposition C. Balancing: Balance the following synthesis reactions: 3. ____ KClO 3  ____ KCl + ____ O 2 4. ____ Al 2 O 3  ____ Al + ____ O 2 2 23 2 4 3

16. III. Types of Reactions - Decomposition D. Chemical Reactions in Words: Write and balance the following equations. Remember to criss-cross and pay attention to diatomic elements (HONCLBrIF). Nitrogen Triiodine decomposes to nitrogen and iodine ___ NI 3  ___ N 2 + ___ I 2 2 13

17. IV. Types of Reactions – Single Replacement A. What is it?  B. General Equation: 2K (s) + 2H(OH) (l)  H 2 (g) + 2KOH (aq) Atoms of one element replace the atoms of a second element in a compound (metal switches with metal or nonmetal switches with nonmetal) Always involves an element and a compound Reaction will only occur if the single element is more reactive than the element in the compound (see Table J) A + BX  B + AX

18. IV. Types of Reactions – Single Replacement  See Table _____ to verify if reaction will occur   ***A metal/nonmetal will replace any metal/nonmetal listed _________  Example: NaCl + Li  NaCl + Mg  NaCl + F 2  NaF + Cl 2  J The element by itself must be above (more reactive) in order for the reaction to occur below it LiCl + Na No reaction NaF + Cl 2 (NOT BALANCED) No reaction

19. IV. Types of Reactions – Single Replacement C. Balancing: Balance the following synthesis reactions: 1. ____ Cl 2 + ____ KBr  ____ KCl + ____ Br 2 2.___ Fe + ____ AgC 2 H 3 O 2  ___ Fe(C 2 H 3 O 2 ) 3 + ____ Ag 3.____ Li + _____ H(OH)  ___ LiOH + ___ H 2 2 2 1 1 1 3 1 3 2 2 2 1

20. IV. Types of Reactions – Single Replacement D. Finish the Chemical Reaction:  Use Table J to see if the following reactions can occur. If it can, write the product and balance the equation (if necessary). Remember to criss-cross and pay attention to diatomic elements (HONCLBrIF). ____ Zn + ____ H 2 SO 4  ___________________________ ____Pb + _____ FeCl 3  ___________________________ ___ ZnSO 4 +___ H 2 1 1 11 No reaction (Pb is BELOW Fe)

21. IV. Types of Reactions – Single Replacement D. Chemical Reactions in Words: Write and balance the following equations. Use Table J to see if the following reactions can occur. If it can, write the product and balance the equation (if necessary). Remember to criss-cross and pay attention to diatomic elements (HONCLBrIF). 1. Calcium reacts with Sodium chloride 2.Potassium reacts with magnesium fluoride 3. Magnesium reacts with zinc nitrate ___ Ca +___ NaCl  ___ CaCl 2 +___ Na 1 21 2 ___ K +___ MgF 2  ___ Mg+___ KF211 2 ___ Mg+___ Zn(NO 3 ) 2  ___ Mg(NO 3 ) 2 +___ Zn 1111

22. V. Types of Reactions – Double Replacement A. What is it?  Occurs only if a solid, gas, or water is formed  Precipitates:  See Table ____: Examples – Cu(NO 3 ) _____Ca 3 (PO 4 ) 2 ____ PbCl 2 ______Ba(OH) 2 ____ Involves an exchange of positive ions between two reacting ionic compounds A solid formed as a product of a reaction that does not dissolve in water (insoluble) F(aq) (s) (aq)

23. V. Types of Reactions – Double Replacement B. General Equation: AX + BY  BX + AY

24. V. Types of Reactions – Double Replacement C. Balancing: Balance the following reactions ____ BaCl 2 (aq) + ____ H 2 SO 4 (aq)  ____ BaSO 4 ( ) + _____ HCl ( ) ____ Al(NO 3 ) 3 (aq) + ___ NaOH (aq)  ____ Al(OH) 3 ( )+ _____ NaNO 3 ( ) ____ Ca(OH) 2 ( ) + ____ H 2 SO 4 ( )  ____ HOH ( ) + ____ CaSO 4 saq 1 1 1 2 s 1 3 1 3 l (s) 1 1 2 1

25. V. Types of Reactions – Double Replacement D. Finish the Chemical Reaction: Balance the following reactions  Write the products and balance the equation (if necessary). Remember to criss-cross. ____ Na 2 S (aq) + _____ Cd(NO 3 ) 2 (aq)  _______________________________ ____ BaCl 2 (aq) + _____ K 2 CO 3 (aq)  _________________________________ ___ NaNO 3 (aq) +___ CdS (s) 11 2 1 ___ BaCO 3 (s) +___ KCl (aq ) 11 12

26. V. Types of Reactions – Double Replacement  Chemical Reactions in Words: 1. Calcium Nitrate + Sodium Carbonate 2. Aluminum nitrate and sodium hydroxide ___ Ca(NO 3 ) 2 (aq) +___ Na 2 CO 3 (aq)  ___ CaCO 3 (s) +___ NaNO 3 (aq) 1 1 1 2 ___ Al(NO 3 ) 3 (aq) +___ NaOH (aq)  ___ Na(NO 3 ) (aq)+___ Al(OH) 3 (s) 1 3 3 1

27. VI. Types of Reactions – Combustion A. What is it?  General Equation: An organic compound (consists of C and H) reacts with oxygen and creates ONLY carbon dioxide (CO 2 ) and water (H 2 O) Organic Compound + O 2  H 2 O + CO 2

28. VI. Types of Reactions – Combustion  Balancing:  Balance the following reactions:  ____ C 4 H 12 + ____ O 2  ____ H 2 O + ___ CO 2 TRICKY!!! ___CH 3 OH + ___O 2  ___H 2 O + ___ CO 2 1 7 6 4 2 3 4 2

29. VII. Stoichiometric Calculations A.Mole- Mole Calculations 1. Given the following equation: 2 C 4 H 10 + 13 O 2 ---> 8 CO 2 + 10 H 2 O, show what the following molar ratios should be. a. C 4 H 10 / O 2 2:13 b. O 2 / CO 2 c. O 2 / H 2 O d. C 4 H 10 / CO 2 e. C 4 H 10 / H 2 O 13:8 13:10 1:4 1:5

30. VII. Stoichiometric Calculations 3 18

31. VII. Stoichiometric Calculations 32 2 32 2 2.50 333

32. VII. Stoichiometric Calculations 1 1 1 1 1 0.417 36.2 1 24