Chemical Reactions and Equations Mr. Guerrero, La Feria High School

Chemical Change-any change in the way that atoms are bonding. A chemical change always forms new substances. Chemical Changes are called reactions and can be represented with a chemical equation. Law of Conservation of Mass- during an ordinary chemical reaction, matter(mass) is neither created nor destroyed.

All chemical equations have 3 parts: Reactants-going to react Yield Sign-during the change Products-the form of matter after the reaction Reactant(s)  Product(s)

Symbols used in equations: + “and” Yield sign, creates (s) Solid (l) Liquid (g) Gas (aq) aqueous solution(substance is dissolved in water) reversible reaction add heat to start reaction Pt catalyst is present

5 Types of Chemical Rxns: 1) Synthesis(Combination) X + Y  XY 2) Decomposition(Breaks down) XY  X + Y 3) Single Replacement A + BC  B + AC *A must have a HIGHER activity than B, See page 278 4) Double Replacement AB + XY  XB + AY (metathesis rxn) 5) Combustion(complete) ________ + O2  CO2 + H2O

Identify the type of rxn and balance: heat + NH3(g)  N2(g) + H2(g) Mg(s) + CuSO4(aq)  Cu(s) + MgSO4(aq)   P4(s)  +   O2(g) →   P2O5(s) + heat C6H6(g) +   O2(g) →   CO2(g) +   H2O(g) Ca(OH)2(aq) +   H3PO4(aq) →   Ca3(PO4)2(s) +   H2O(l) + 3300kJ

Identify the type of rxn and balance: Cr(s) +  O2(g) →  Cr2O3(s) AgNO3(aq) +  K3PO4(aq) →  Ag3PO4(s) +  KNO3(s) Al(s) + Fe2O3(aq)  Fe(s) + Al2O3(aq) + heat C3H8(g) +  O2(g) →  CO2(g) +  H2O(g)  heat + Al2O3(s) →  Al(s) +  O2(g)