Chemical Reactions Chap 7 (sections 1 and 2)

Chemical Reactions: The basics Reactants – substances that undergo the change (the “before”) Products – new substance that forms (the “after”) C + O 2  CO 2 Reactants =Product(s) =

Balancing Chemical Reactions During chemical reactions the mass of the products = the mass of the reactants H 2 + O 2  H 2 O Reactants # of H = # of O = Products # of H = # of O = To balance out the # of atoms on each side, use coefficients Coefficients = numbers that appear BEFORE the formulas WARNING!! Do not change the subscripts in a formula

Balancing Chemical Reactions Law of Conservation mass is neither created nor destroyed during chemical reactions ___H 2 + ___O 2  ___H 2 O What coefficients can be added to balance the equation??

Balancing these reactions Na + H 2 O  NaOH + H 2 Al + Cl 2  AlCl 3

Types of Chemical Reactions 1.Synthesis – “to make” 2.Decomposition – “to break down” 3.Single Replacement – “1 swaps places with another” 4.Double Replacement – “2 swap places with others” 5.Combustion – “react with oxygen” usually creates heat and light Heads up!! Some chemical reactions can fit into multiple categories

Synthesis A + B  AB DEMO – Magnesium and oxygen Mg + O 2  MgO Magnesium Metal combining with oxygen

Decomposition AB  A + B DEMO H 2 CO 3  CO 2(g ) + H 2 O (l ) Carbonic acid decomposing when in pop

Single Replacement A + BC  B + AC DEMO – Sodium Metal in water Na + H 2 O  NaOH + H 2 Sodium Metal Reacting with Water

Double Replacement AB + CD  AD + CB DEMO KI + Pb(NO 3 ) 2  KNO 3 + PbI 2

Combustion Mg + O 2  MgO DEMO – Magnesium and oxygen Mg + O 2  MgO Burning of Magnesium Metal

Identify the reaction type 2C 2 H 6 +7O 2  4CO 2 + 6H 2 O Pb(NO 3 ) 2 + 2HCl  PbCl 2 + 2HNO 3 Ca + 2HCl  CaCl 2 + H 2 2SO 4 + O 2  2SO 3