Types of Chemical Reactions

1. Types of Chemical Reactions Section 3.3

2. Overview • At the end of this lesson you will be able to: • Predict the products of five types of chemical reactions, given the reactants and balance the resulting chemical equation

3. Review • What is the formula for the following compounds? • Magnesium nitrate • Potassium iodide • Calcium phosphate • Nitrogen trichloride • Carbon dioxide • What ions can combine? • How do we find state of ionic compounds?

4. Types of Chemical Reactions • There are five types of chemical reactions: • Formation • Decomposition • Combustion • Single replacement • Double replacement • What do you think each of these mean? Any guesses?

5. Formation Reactions • Also called synthesis reaction • Simplest form, two elements combine to form a compound • Element + element  compound • A + B  AB • Ex. S8(s) + 8O2(g) 8SO2(g)

6. Formation Reactions • Can be more complex • Compound + compound  compound • Ex. CO2(g) + H2O(l) H2CO3(aq) • For more complex formation reactions where one reactant is a metal and one a non-metal, write the ionic compound that would be formed

7. Decomposition Reactions • Breaking down compounds into its constituent parts • Compound  element + element • AB  A + B • Only one reactant • Ex. 2 H2O(l) 2 H2(g) + O2(g)

8. Combustion Reactions • Burning in the presence of oxygen • Exothermic? Endothermic? • The products are the oxides of the elements present in the reactants – compounds with oxygen bonded to another element • Generally, the product is most common oxide

9. Combustion Reactions • Be familiar with these most common oxides: • carbon, then CO2(g) is formed • hydrogen, then H2O(g) is formed • sulfur, then SO2(g) is formed • nitrogen, then NO2(g) is formed • a metal, then the most common oxide of that metal is formed

10. Hydrocarbon Combustion • A type of combustion reaction • Hydrocarbon- substances containing hydrogen and carbon • General formula: CxHy(x= # carbons, y= # hydrogens) • Combine with O2(g) to make two products: CO2(g) and H2O(g) CxHx + O2 (g) → CO2 (g) + H2O (g) CH4 (g) + 2 O2 (g)→ CO2 (g)+ 2 H2O (g)

11. Combustion Reactions • Other combustion examples: C3H8(g) + 5 O2(g)→ 3 CO2(g) + 4 H2O(g) 2 Na2S(s) + 3 O2(g)→ 2 Na2O(s) + 2 SO2(g) 4 Fe(s) + 3 O2(g) → 2 Fe2O3(s) 4 NH3(g) + 7 O2(g) → 4 NO2(g) + 6 H2O(g)

12. Single Replacement Reactions • Single element replaces another element in a compound • A + BC  B +AC • Mg(s) + 2 AgNO3(aq) 2 Ag(s) + Mg(NO3)2(aq)

13. Double Replacement Reactions • Element of each of two compounds switch places • AB + CD AD + CB • Be careful! • Make sure only combining positive ions with negative ions (i.e. cannot put positive-positive together) • Positive ions appear first and negative ions second

14. Questions?

15. Predicting and Balancing • Double Replacement Reactions: • Aqueous lead(II) nitrate and aqueous sodium iodide are mixed and a yellow precipitate forms. Predict the products, writing out the balanced formula equation, including states

16. Practice • Write the formula equation, predict the products, and balance the following (include states!): • When aqueous copper(I) nitrate and aqueous potassium bromide are mixed, a precipitate forms • Aluminium chloride and sodium hydroxide are mixed, creating a precipitate • Ni(NO3)3(aq) + Na2SO3(aq)

17. Practice: Single Replacement • Write the formula equation, predict the products and balance the following: • Aluminium metal and copper(II) chloride react together • Chlorine gas is added to a solution of aqueous nickel(III) bromide • Zinc metal is placed into a solution of silver nitrate

18. Practice: Decomposition • Predict the products and balance the following equations • ___MgS(s) • ___KI(s)  • ___Al2O3(s)  • ___NiCl2(s) 

19. Practice: Formation • For the following equations give the product and balance • sodium + sulfur  • magnesium + oxygen  • Iron + chlorine 

20. Practice: Combustion • Complete and balance each equation: • ___CH4(g) + ___O2(g) • ___C2H6(g) + ___O2(g)  • ___C3H8(g) + ___O2(g)  • ___C6H6(l) + ___O2(g) 