Names: ____________________________________________________________ Date: __________Period: __________
Boiling point is a physical property. This is the temperature at which a
substance changes rapidly from its liquid state into a gas. Rapid formation of
bubbles is evidence that the liquid is at its boiling temperature. Liquids with
higher boiling points tend to have lower rates of evaporation. In this
experiment you will identify the boiling point of fresh and salt water.
Materials:
Laptop
Logger Pro software
Temperature Probe
250mL Beaker
Salt
Spoon
Ring Stand
Clamp
Hot Plate
Water
Digital Scale
Procedure:
1. Obtain and wear goggles. Hot boiling salt water can hurt your skin and eyes. Please handle all tools with care
throughout the experiment.
2. Prepare the water sample:
a. Arrange a hot plate next to the base of a ring stand as shown in Figure 1.
b. Fill a 250mL break with 200mL of water.
c. Add and stir to dissolve 7.25 grams of salt. You will have to stir for a few minutes for all the salt to
dissolve. If it doesn’t all dissolve, stir for the first few minutes of heating later in the lab.
d. This will create a 34,981.9 ppm (part per million) solution. Ocean water is approximately 35,000 ppm.
e. Place the beaker on the hot plate.
f. Using the clamp, suspend a temperature probe from the ring stand. The probe should be 1 – 2 cm above
the bottom of the beaker. Be careful you or the probe wire does not touch the hot plate.
3. Open LoggerPro. Follow directions to set up the program.
4. Turn on the hot plate to high and start collecting data in LoggerPro.
5. When the water has boiled with noticeable bubbling for six minutes, carefully:
a. Stop the data collection.
b. Turn off the hot plate.
c. Remove the temperature probe.
Observations
Using the data you collected, determine the boiling point of salt water. Sketch your graphs for both Fresh (demo) and
Salt water below. Label the boiling point of each. Save the “Boiling Point of Salt Water” image to your I drive.
Boiling Point of Salt Water
Names: ____________________________________________________________ Date: __________Period: __________
Analysis
1. Look at your graph. What happened to the temperature of the water as it was heated prior to boiling?
2. Look at your graph. What happened to the temperature of the water as it boiled?
3. What is the approximate boiling point of fresh water? ______ ⁰C
4. What is the approximate boiling point of salt water? ______ ⁰C
5. Are there any differences in boiling points between the fresh and salt water? If so explain.
6. Which liquid is more likely to have a higher rate of evaporation? Fresh or Salt Water? How would this
relate to our study of the ocean?
7.
List two factors that could influence the salinity of ocean water.
a. ___________________________________________
b. ___________________________________________
Graph interpretation
Write a true statement about the relationship between
temperature and salinity between 80⁰N and 23⁰N and 80⁰S
and 23⁰S.
Write a true statement about the relationship between
Temperature and salinity between 23⁰N and 23⁰S.
Attempt to write a statement explaining why the relationship
changes.