Temperature change

• What should you be able to describe by the end of the video on temperature changes in chemical reactions?

  How to investigate the variables that affect temperature changes in chemical reactions
• What type of reaction is being investigated in this practical?

  An exothermic reaction
• What is the neutralization reaction being studied in this experiment?

  The reaction between hydrochloric acid and sodium hydroxide
• What is the independent variable in this experiment?

  The volume of sodium hydroxide solution
• What is the dependent variable in this experiment?

  The maximum temperature reached
• What are the control variables in this experiment?

  The volume of hydrochloric acid and the concentrations of both solutions
• How do you prepare the hydrochloric acid for the experiment?

  Measure 30 centimeters cubed of dilute hydrochloric acid
• Why do we place the polystyrene cup inside a beaker?

  To prevent the cup from falling over
• What is the purpose of the thermometer in this experiment?

  To measure the temperature of the acid and the solution
• What happens to the temperature of the solution during the exothermic reaction?

  The temperature of the solution increases
• What should you do when the thermometer reading stops changing?

  Record the highest temperature reached
• What is the next step after measuring the temperature with 5 centimeters cubed of sodium hydroxide solution?

  Repeat the experiment using 10 centimeters cubed of sodium hydroxide solution
• How many times do you increase the volume of sodium hydroxide solution in the experiment?

  Until reaching a maximum of 40 centimeters cubed
• What can you calculate from the two sets of results obtained in the experiment?

  A mean value for the maximum temperature reached for each volume of sodium hydroxide solution
• What trend is observed when increasing the volume of sodium hydroxide solution?

  The maximum temperature reached increases initially
• Why does the maximum temperature start to decrease after a certain volume of sodium hydroxide solution?

  There is not enough hydrochloric acid to react with all the sodium hydroxide
• What happens to the energy released when large volumes of sodium hydroxide solution are added?

  The energy released is spread out into a greater volume
• Why is a polystyrene cup with a lid used in this experiment?

  To reduce heat losses
• What property of polystyrene makes it suitable for this experiment?

  It is a good thermal insulator
• What type of questions can be found in the vision workbook related to this practical?

  Questions on the required practical
• What is the procedure for measuring the temperature of the acid before adding sodium hydroxide?

  Use a thermometer to measure the temperature of the acid and record it in a table
• Why is it important to stir the solution gently with the thermometer?

  To ensure even distribution of temperature throughout the solution
• Why do we record results in a table during the experiment?

  To keep track of the maximum temperatures reached for each volume
• How do you plot a graph of results from the experiment?

  By plotting the maximum temperature against the volume of sodium hydroxide solution
• Why does the maximum temperature reached increase with more sodium hydroxide?

  More particles of sodium hydroxide react with hydrochloric acid, releasing more energy
• What is the role of energy release in exothermic reactions?

  It causes the temperature of the solution to increase
• What is the purpose of the plastic lid in the experiment?

  To minimize heat loss to the air