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CHEMICAL CHANGES CHEMICAL CHANGES CAN EITHER BE EXOTHERMIC OR ENDOTHERMIC EXOTHERMIC: A CHEMICAL CHANGE THAT INVOLVES THE RELEASE OF HEAT. EX: BURNING A MATCH
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CHEMICAL CHANGES CHEMICAL CHANGES CAN EITHER BE EXOTHERMIC OR ENDOTHERMIC EXOTHERMIC: A CHEMICAL CHANGE THAT INVOLVES THE RELEASE OF HEAT. EX: BURNING A MATCH ENDOTHERMIC: A CHEMICAL CHANGE THAT INVOLVES THE ABSORPTION OF HEAT. EX: COOKING (HEAT GOES FROM THE STOVE INTO THE COLD FOOD TO HEAT IT)
RATE OF CHEMICAL CHANGES HOW FAST A CHEMICAL CHANGE HAPPENS DEPENDS ON: THE TEMPERATURE – THE HIGHER THE TEMPERATURE, THE FASTER THE REACTION 2. THE CONSENTRATION – THE HIGHER THE CONSENTRATION OF A CHEMICAL, THE FASTER THE REACTION 3. SURFACE AREA – MATERIAL THAT IS BROKEN INTO PIECES WILL REACT FASTER THAT MATERIAL THAT IS WHOLE
CONSERVATION OF MASS ALL CHEMICAL REACTIONS HAVE 2 PARTS: REACTANTS AND PRODUCTS. EX: Na + Cl NaCl reactants products ALL CHEMICAL REACTIONS MUST BE BALANCED IN BOTH SUBSTANCE AND MASS. THIS MEANS THAT WHICHEVER CHEMICALS YOU START WITH YOU WILL END WITH, AND YOUR STARTING MASS AND ENDING MASS WILL BE THE SAME.
BALANCING EQUATIONS ALL CHEMICAL EQUATIONS MUST BE BALANCED, WHICH MEANS THE NUMBER OF ATOMS OF AN ELEMENT MUST BE THE SAME IN BOTH THE REACTANTS AND PRODUCTS. WE BALANCE EQUATIONS BY ADDING COEFFICIENTS. EX: Fe + O2 Fe2O3 1 iron 2 oxygen 2 iron, 3 oxygen UNBALANCED ADD COEFFICIENTS 4Fe + 3O2 2Fe2O3 4 iron 6oxygen 4 iron, 6 oxygen BALANCED (3x2=6)
TEST YOUR SKILLS Na + Cl2 NaCl 1 Sodium + 2 Chlorine 1 Sodium + 1 Chlorine UNBALANCED H2 + O2 H2O 2 Hydrogen + 2 Oxygen 2 Hydrogen + 1 Oxygen UNBALANCED N2 + 3H2 2NH3 2 Nitrogen + 6 Hydrogen 2 Nitrogen + 6 Hydrogen BALANCED