11.3 Temperature Changes

• What type of reaction is being investigated in the experiment?

  Neutralization reaction
• What are the two substances used in the experiment?

  Hydrochloric acid and sodium hydroxide
• Why are safety goggles used during the experiment?

  To protect the eyes from harmful substances
• What is the purpose of placing the polystyrene cup in a beaker?

  To prevent tipping over and spilling the acid or alkali
• Why is a polystyrene cup and lid used in the experiment?

  To minimize heat loss during the reaction
• How much hydrochloric acid is poured into the measuring cylinder?

  30 cm³
• How should the hydrochloric acid be measured for accuracy?

  By reading to the bottom of the meniscus
• What is the initial temperature recorded in the experiment?

  24° C
• How much sodium hydroxide is measured for the first addition?

  5 cm³
• What should be done after adding sodium hydroxide to the cup?

  Stir gently with the thermometer to distribute heat
• What is the maximum temperature recorded after adding 5 cm³ of sodium hydroxide?

  26° C
• What is the procedure for subsequent additions of sodium hydroxide?

  Add 5 cm³ more each time and record the temperature
• What is the total volume of sodium hydroxide after the second addition?

  10 cm³
• Why is it important to add sodium hydroxide quickly?

  To minimize heat loss during the reaction
• What is the maximum temperature reached after adding 10 cm³ of sodium hydroxide?

  27° C
• What happens to the temperature as more sodium hydroxide is added?

  The temperature may level out or drop at larger quantities
• What concept should be considered regarding limiting reactants in this experiment?

  How limiting reactants affect the temperature change
• What is the main focus of this experiment?

  To observe temperature changes in an exothermic reaction