Chemical Changes – Part Deux
Types of chemical changes Synthesis & Decomposition Precipitation Oxidation Combustion Acid-Base Neutralization Cellular Respiration & Photosynthesis
1. Synthesis and Decomposition Synthesis Reaction: The combination of two or more reactants to form a new product Decomposition: The separation of a compound into two or more compounds or elements 2H2 + O2 2H2O A + B AB 2H2O 2H2 + O2 AB A + B
2. Precipitation
2. Precipitation CdSO4 (aq) + K2S (aq) → CdS (s) + K2SO4 (aq) 2 NaOH (aq) + MgCl2 (aq) → 2 NaCl (aq) + Mg(OH)2(s) CuSO4 (aq) + 2NaOH (aq) → Cu(OH)2 (s) + Na2SO4 (aq)
2. Precipitation Formation of an insoluble, or only slightly soluble, solid substance (precipitate), when two aqueous solutions are combined
3. Oxidation
Oxidation Chemical change involving oxygen or a substance with properties similar to those of oxygen
4. Combustion – a type of oxidation Form of oxidation that releases a large amount of energy
5. Acid-Base Neutralization Reaction of an acid with a base to form a salt and water Acid (aq) + Base (aq) Salt (aq) + Water (l) If H+ = OH- ? If H+ > OH- ? If H+ < OH- ? H+ ions OH- ions
Heart Burn Stomach Acid + Antacid Salt + Water
Neutralization of HCl and NaOH HCl (aq) + NaOH (aq) NaCl (aq) + H2O (l) HCl (aq) H+ (aq) + Cl- (aq) NaOH (aq) OH- (aq) + Na+(aq) H2O NaCl
Recognizing Acid-Base Neutralization Reactions HCl (aq) + NaOH (aq) NaCl (aq) + H2O (l)