CHEMICAL REACTIONS

1. CHEMICAL REACTIONS The process by which one or more substances are changed into one or more different substances

2. Word Equations • To write a word equation, • Write the names of the reactants to the left of the arrow separated by plus signs; • Write the names of the products to the right of the arrow, also separated by plus signs. Reactant + Reactant  Product + Product

3. EXAMPLE • Methane + Oxygen  Carbon dioxide + Water

5. EXAMPLE 2 • Iron + Oxygen  Iron(III) Oxide

6. EXAMPLE 3 Hydrogen Peroxide  Water and Oxygen catalase

7. Skeleton Equations • Write the formulas of the reactants to the left of the yields sign (arrow) and the formulas of the products to the right. • A skeleton equation is a chemical equation that does not indicate the relative amounts of the reactants and products. • Here is the equation for rusting: • Fe + O2 Fe2O3

8. Formula Writing Practice WS

9. Catalyst • A catalyst is a substance that speeds up the reaction but is not used up in the reaction • Without catalyst With Catalyst

10. Important Symbols

11. Balancing Chemical Equations • To write a balanced chemical equation, • Write the skeleton equation • Use coefficients to balance the equation so that it obeys the law of conservation of mass. • Remember you want the same number of atoms of each element on each side of the equation.

12. Example

13. Example 2

14. Example 3 -- Try on your own!!! • Write a balanced chemical equation for the reaction in which sodium hydroxide and calcium bromide react to produce solid calcium hydroxide and sodium bromide. (The reaction occurs in water.) NaOH(aq)+CaBr2(aq) Ca(OH)2(s)+NaBr(aq) 2NaOH(aq)+CaBr2(aq) Ca(OH)2(s)+2NaBr(aq)

15. Summary

16. Warm Up!! • _____NaClO3 →____ NaCl + __O2

17. Chemical Equations from Names • Magnesium and Hydrogen Chloride produce Hydrogen and Magnesium Chloride • Calcium Hydroxide and Lithium Chloride produce Lithium Hydroxide and Calcium Chloride • Decompose Copper (II) oxide into Copper and Oxygen • Aluminum and Iron (III) oxide produce iron and aluminum oxide • combustion of Butane (C4H10) in air to produce carbon dioxide and water

18. Warm Up • ___AgNO3 + __Ni  __Ni(NO3)2 + __Ag

19. The Five Types of Reactions

20. Chemistry with Synthesis Reactions A + B  AB

21. 1. Synthesis Reactions (Combination) • Two or more reactants produce one product • Examples: NH3 + HCl  NH4Cl H2 + O2 H2O Ag + S  Ag2S Al + Cl2 AlCl3

22. Chemistry with Decomposition Reactions AB  A + B

23. 2. Decomposition • One reactant produces two or more products • Examples Ag2O Ag + O2 PCl5 PCl3 + Cl2 H2O2 H2O + O2 CuO Cu + O2

24. Chemistry with Single Replacement AB + C  AC + B

25. 3. Single Replacement • One element replaces another element • Must consult the activity series

26. 3. Single Replacement • One element and one compound producing a different element and compound • Examples Fe + H3(PO4)  H2 + Fe3(PO4)2 H2 + CuO  Cu + H2O Zn + HCl  H2 + ZnCl2 Cl2 + KBr  Br2 + KCl

27. Equations Activity Series Worksheet

28. Chemistry with Double Replacement AB + CD  AD + CB

29. 4. Double Replacement A double-replacement reaction is a chemical change involving an exchange of positive ions between two compounds. • Examples: Al(NO3)3 + NaOH  Al(OH)3 + NaNO3 PbCl2 + Li2SO4 PbSO4 + LiCl ZnBr2 + AgNO3 Zn(NO3)2 + AgBr BaCl2 + KIO3 Ba(IO3)2 + KCl

30. 4. Double replacement • Three main products of a double replacement reaction • Precipitate (solubility table) • Water • Gas

31. 5. Combustion • A combustion reaction • Chemical change • Element or a compound reacts with oxygen • Producing energy in the form of heat and light

32. 5. Combustion A hydrocarbon reacts with oxygen to produce carbon dioxide and water Examples: CH4 + O2 CO2 + H2O C6H12O6 + O2 CO2 + H2O