Heat of Neutralization Lab
Heat of Neutralization Lab Objective: The objective of this lab was to measure, using a calorimeter, the energy changes accompanying neutralization reactions. Background: Chemical changes are always accompanied by a change in energy, typically as heat. If the reaction releases heat (ΔH < 0) then the reaction is exothermic. If the reaction absorbs heat (ΔH > 0) then the reaction is endothermic. The quantity of heat is measured experimentally by having the reaction take place in an insulated container called a calorimeter. It must be taken into account, however, that some of the heat released or absorbed in the reaction will be absorbed by the calorimeter itself. This amount must be determined experimentally and is referred to as the heat capacity of the calorimeter. This means the amount of heat required to raise the temperature 1 kelvin. The heat capacity of the calorimeter can be determined by using the following equation:
ΔH =− ΔT (heat capacity of calorimeter + heat capacity of contents) Procedure:
A. Heat Capacity of Calorimeter
Construct a calorimeter by nesting two Styrofoam cups together. Use a cork borer to make a hole in the lid just big enough to admit the thermometer; then slip the thermometer into a split onehole rubber stopper, which prevents you from placing the thermometer too deeply in the calorimeter. The thermometer should not touch the bottom of the cup. Rest the entire appartus in a 400 mL beaker to provide stability. Place exactly 50.0 mL of distilled water in the calorimeter cup and replace the cover and thermometer. Allow 5 to 10 minutes for the system to reach thermal equilibrium; then record the temperature to the nearest 0.1°C on the report sheet. Place exactly 50.0 mL of distilled water in a clean, dry 250 mL beaker and heat the water with a low flame until the temperature is approximately 15° to 20°C above room temperature. Do not heat to boiling; otherwise appreciable water will be lost,
ΔH =− ΔT (heat capacity of calorimeter + heat capacity of contents) Procedure:
A. Heat Capacity of Calorimeter
Construct a calorimeter by nesting two Styrofoam cups together. Use a cork borer to make a hole in the lid just big enough to admit the thermometer; then slip the thermometer into a split onehole rubber stopper, which prevents you from placing the thermometer too deeply in the calorimeter. The thermometer should not touch the bottom of the cup. Rest the entire appartus in a 400 mL beaker to provide stability. Place exactly 50.0 mL of distilled water in the calorimeter cup and replace the cover and thermometer. Allow 5 to 10 minutes for the system to reach thermal equilibrium; then record the temperature to the nearest 0.1°C on the report sheet. Place exactly 50.0 mL of distilled water in a clean, dry 250 mL beaker and heat the water with a low flame until the temperature is approximately 15° to 20°C above room temperature. Do not heat to boiling; otherwise appreciable water will be lost,