Endothermic and Exothermic Reaction

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EXPERIMENT # 14: Exothermic and endothermic reactions
Date: 25/06/2012Name: Meagen Reyes Year 11 PARTS A, B and C * For the procedures and equipment needed in these experiments, refer to page 73-74 in the STAWA Exploring chemistry stage 2 book Part A: solution process (dissociation)

Solutions and their chemical equations| Initial temperature (in Celsius)| Final temperature (in Celsius)| Classification(exothermic or endothermic)| Sodium hydroxide NaOH(s) Na+(aq) + OH-(aq) + Energy| 15°C | 35°C| exothermic| Ammonium ChlorideNH4Cl(s) + Energy NH4+(aq) + Cl-(aq) + H2O(l) | 15°C| 10°C| endothermic| Sodium AcetateC2H3O2-(aq) + Energy HC2H3O2(aq) + OH-(aq)| 15°C| 11°C| endothermic| Sodium ChlorideNaCl(s) + Energy Na+(aq) + Cl-(aq)| 15°C| 13°C| endothermic| PART B: Reaction between ammonium thiocyanate and barium hydroxide NH4SCN(s) + Ba [(OH)2]4(s) + Energy NH3(g) + H2O(l) + SCN-(aq) + Ba2+(aq) This reaction was between ammonium thiocyanate and barium hydroxide which were both dry white powders. When these chemicals were mixed my first observation was that it turned slurry then it eventually liquefied so I assumed that the product formed was water. The next thing I observed was when the beaker was lifted up, the wooden block became attached to it because the water froze in between them. This phenomenon showed that the temperature dropped. If we could smell the reaction vessel we would sense the strong pungent odor of ammonia like the ones found in household bleach. Since the heat energy was absorbed by the system and the temperature decreased, I therefore conclude that it was an endothermic reaction. PART C: Reaction between iron and COPPER (II) sulfate solution The experiment and its chemical equation| Initial temperature (in Celsius)| Final temperature (in Celsius)| Classification (exothermic or endothermic)| Description| Iron with copper (II) sulfate Fe + CuSO4 FeSo4 + Cu + Energy| 15°C| 19°C| exothermic| The steel...
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