Required Practical 4:Temperature Change

• What should you be able to describe by the end of the video?

  Investigate variables affecting temperature changes
• What type of reaction is being investigated in this practical?

  Exothermic reaction
• What is the neutralization reaction being studied?

  Hydrochloric acid and sodium hydroxide
• What is the independent variable in this experiment?

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

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

  Volume and concentrations of acids and bases
• How do you measure the hydrochloric acid for the experiment?

  Using a measuring cylinder to measure 30 cm³
• Why is the polystyrene cup used in the experiment?

  To reduce heat loss during the reaction
• What should be done after adding sodium hydroxide to the acid?

  Fit a plastic lid and stir gently
• What happens to the temperature during an exothermic reaction?

  The temperature of the solution increases
• What is observed when the thermometer reading stops changing?

  Record the highest temperature reached
• What is done after measuring the temperature for 5 cm³ of sodium hydroxide?

  Repeat the experiment with 10 cm³
• How much sodium hydroxide is added each time?

  Increase by 5 cm³ each time
• What happens to the maximum temperature as sodium hydroxide volume increases?

  It initially increases, then decreases
• Why does the maximum temperature decrease after a certain volume of sodium hydroxide?

  Not enough hydrochloric acid to react
• What happens to the energy released when more sodium hydroxide is added?

  It spreads out into a greater volume
• Why is a lid used in the experiment?

  To reduce heat loss to the air
• Where can you find more questions on this practical?

  In the vision workbook linked above
• What are the specific volumes of sodium hydroxide used in the experiment?

  5 cm³ to 40 cm³
• How is the mean value for maximum temperature calculated?

  By averaging two sets of results
• Why is it important to plot a graph of results?

  To visualize the relationship between variables
• How does the number of sodium hydroxide particles affect energy released?

  More particles release more energy
• What is the role of the thermometer in the experiment?

  To measure the temperature of the solution
• What is the role of the beaker in the experiment?

  To stabilize the polystyrene cup