Lab 8- Revision quiz

What does a surfactant do to surface tension?

• Changes its direction

• Has no effect

• Increases it

• Decreases it

What is the lowest concentration of surfactant at which micelles begin to form called?

• Critical Micelle Concentration

• Surface Tension Point

• Micelle Formation Point

• Surfactant Threshold

Which of the following is an example of a non-ionic surfactant?

• Tween

• Sodium Lauryl Sulfate

• Cetyl Trimethyl Ammonium Bromide

• Benzalkonium Chloride

What happens to surface tension after reaching CMC?

• It remains constant

• It increases

• It fluctuates

• It decreases

How many times should you repeat the drop counting step for calibration?

• One time

• Two times

• Three times

• Four times

What is the purpose of using different concentrations of Tween in the experiment?

• To find the average drop count

• To calibrate the stalagmometer

• To determine the CMC

• To increase surface tension

What is the effect of increasing surfactant concentration beyond CMC?

• No effect on micelles

• Destroys micelles

• Increases micelles

• Decreases micelles

What is the concentration of Tween used in the first trial of the experiment?

• 0.18%

• 0.09%

• 0.12%

• 0.15%

What is the relationship between micelles and surfactant concentration after CMC?

• Micelles increase

• Micelles remain constant

• Micelles decrease

• Micelles disappear