IIIIIIIVV I.Intro to Reactions Chemical Reactions

A.Signs of a Chemical Reaction n Evolution of heat and light n Formation of a gas n Formation of a precipitate n Color change

B.Law of Conservation of Mass n mass is neither created nor destroyed in a chemical reaction 4 H 2 O 4 H 2 O 4 g32 g 36 g n total mass stays the same n atoms can only rearrange

C. Chemical Equations A+B  C+D REACTANTSPRODUCTS

IIIIIIIVV Chemical Reactions III. Types of Chemical Reactions

A. Combustion CH 4 (g) + 2O 2 (g)  CO 2 (g) + 2H 2 O(g) n the burning of any substance in O 2 to produce heat A + O 2  B

Na(s)+ O 2 (g)  C 3 H 8 (g)+ O 2 (g)  A. Combustion n Products:  contain oxygen  hydrocarbons form CO 2 + H 2 O CO 2 (g)+ H 2 O(g) Na 2 O(s) 4 2

B. Synthesis n the combination of 2 or more substances to form a compound n only one product A + B  AB

B. Synthesis H 2 (g) + Cl 2 (g)  2 HCl(g)

Al(s)+ Cl 2 (g)  AlCl 3 (s) B. Synthesis n Products:  ionic - cancel charges  covalent - hard to tell

C. Decomposition n a compound breaks down into 2 or more simpler substances n only one reactant AB  A + B

C. Decomposition 2 H 2 O(l)  2 H 2 (g) + O 2 (g)

KBr(l)  K(s) + Br 2 (l) 2 2 C. Decomposition n Products:  binary - break into elements  others - hard to tell

D. Single Replacement n one element replaces another in a compound  metal replaces metal (+)  nonmetal replaces nonmetal (-) A + BC  B + AC

D. Single Replacement Cu(s) + 2AgNO 3 (aq)  Cu(NO 3 ) 2 (aq) + 2Ag(s)

Fe(s)+ CuSO 4 (aq)  Cu(s)+ FeSO 4 (aq) D. Single Replacement n Products:  metal  metal (+)  nonmetal  nonmetal (-)  free element must be more active (check activity series) Br 2 (l)+ NaCl(aq)  N.R.

Activity Series

AB + CD  AD + CB E. Double Replacement n ions in two compounds “change partners” n cation of one compound combines with anion of the other

E. Double Replacement Pb(NO 3 ) 2 (aq) + K 2 CrO 4 (aq)  PbCrO 4 (s) + 2KNO 3 (aq)

Pb(NO 3 ) 2 (aq)+ KI(aq)  PbI 2 (s)+ KNO 3 (aq) E. Double Replacement n Products:  switch negative ions  one product must be insoluble (check solubility table) NaNO 3 (aq)+ KI(aq)  N.R. 2 2

Identify the type of Rxn a)Mg + 2HCl  MgCl 2 + H 2 b)3Ca + N 2  Ca 3 N 2 c)NH 4 NO 3  N 2 O + 2H 2 O d)2BiCl 3 + 3H 2 S  Bi 2 S 3 + 6HCl

Identify type of Rxn e)2C 4 H O 2  8CO H 2 O f)6O 2 + C 6 H 12 O 6  6CO 2 + 6H 2 O h)Cr 2 (SO 4 ) 3 + 6NaOH  2Cr(OH) 3 + 3Na 2 SO 4