Exploring Stoichiometry in Reactions

What is the purpose of using phenolphthalein in a titration experiment?

• To measure the volume of reactants

• To act as a catalyst

• To indicate the endpoint of the titration by changing color

• To increase the reaction rate

Why is it important to wear closed-toed shoes in the lab during an experiment?

• To prevent static electricity buildup

• To increase comfort while standing

• To maintain a professional appearance

• To prevent chemical spills on the feet

What is the first step in using a volumetric pipet?

• Drawing up the solution to the marked line

• Rinsing it with the solution to be used

• Measuring the required volume of reactant

• Adding a bulb or pump

How many times should the burette be rinsed with the solution before use?

• 2 times

• 1 time

• 3 times

• 4 times

What indicates that the endpoint of a titration has been reached when using phenolphthalein?

• The solution turns clear

• The solution turns pink and remains so with swirling

• The solution bubbles

• The solution becomes colorless

What should be done if you overshoot the mark on the volumetric pipet?

• Continue with the experiment

• Discard the excess into a waste beaker

• Add more solution to adjust

• Record the actual volume used

What base is used in the first titration experiment described?

• Sulfuric acid

• Sodium hydroxide

• Ammonium hydroxide

• Hydrochloric acid

Which acid is titrated with sodium hydroxide in the second experiment?

• Citric acid

• Hydrochloric acid

• Acetic acid

• Sulfuric acid

In the final experiment, what is the base used in the burette?

• Sodium hydroxide

• Hydrochloric acid

• Sulfuric acid

• Ammonium hydroxide

What is the correct procedure if the final color of the titration persists after swirling?

• Start the experiment over

• Record the volume at which the color changed

• Continue adding base

• Add more indicator