8P1.3 Lab
For today’s lab we will investigate changes in chemical and physical properties to allow us to determine
if a chemical reaction as taken place. Be sure to be careful when determining if you have observed a
change in a chemical or physical property. Once you have observed and determined what changes have
taken place infer what those changes could mean to determine if a chemical reaction (chemical change)
has taken place.
Materials:
2 Beakers
Dropper
pH sensor or litmus paper
2 tablets of Sodium Hydroxide / 25 ml or Sodium Hydroxide solution
5ml of Phenolphthalein
Directions
Start by making sure you have access to all of your needed materials and that your containers are cleaned
and dried.
1. If you have sodium hydroxide solution, pour 25 ml of sodium hydroxide solution into a small
beaker. / If you do not have solution, place 1 or 2 tablets of sodium hydroxide into a larger
beaker, then smash them into a powder by placing the flat bottom of a smaller beaker over them
and pushing down multiple times. You can also use a mortar and pestle if you have them
available. Once you have crushed up the sodium hydroxide pour 25 ml of water into the beaker
and stir using your dropper until the powder has dissolved into the water.
2. Use your pH sensor or litmus paper to record the pH of your sodium hydroxide solution.
pH=____________
3. Use your dropper to add one drop at a time of phenolphthalein to your solution.
4. Observe and record any occurrences you witness after each drop.
Drop 1. ________________ , Drop2 _____________, Drop 3 _____________, Drop 4
_____________ Drop 5. ____________________________________________
5. After you have added 4 drops of phenolphthalein to your solution use your pH sensor or Litmus
paper to record the pH of your solution. pH = ___________
Questions:
1. What changes did you observe during this experiment? For each change explain if this was a
change in a physical or chemical property.
2. Did a chemical reaction take place? What is your evidence to support your conclusion?