Answer:
In this activity, you will complete a virtual experiment to identify the unknown compounds. Use the interactive on the assessment page to collect your data.
Pre-lab Questions:
1. What are the properties of ionic compounds? They form Crystals
2. What are the properties of covalent compounds?
3. Which type of compound is salt? They are usually Gasses
4. Which type of compound is sugar? disaccharides
Hypothesis
Record your hypothesis as an “if, then” statement for the rate of dissolving the compounds:
If I apply heat the compounds Should dissolve faster
Variables
List the independent, dependent, controlled variables of the experiment.
The independent variables of Ionic compounds are Usually liquid or gasses at room temperature.
Materials
(Note: this is a virtual lab, no materials are needed. The items listed here are the types of items that could be used in a similar investigation.)
• a hot plate
• a thermometer
• a scale
• a measuring spoon
• water
• beakers
Procedure
Remember this is a virtual lab. You do not need to actually perform these steps, but follow along and collect the data!
1. Measure out 100 mL of water into three beakers and label them A, B, and C. Beaker C will be the control.
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2. Then measure 50 grams of unknown compound A into beaker A and stir for one minute. Measure the amount of undissolved solute and record this in Table 1.
3. Then measure 50 grams of unknown compound B into beaker B and stir for one minute. Measure the amount of undissolved solute and record this in Table 1.
4. Next, we will test the boiling point of each solution. Place each beaker onto a hot plate.
5. When the solution boils, use a thermometer to record the temperature. Record the boiling point for each solution in Table 2.
Data Table 1
Record the amount of solute left after one minute of stirring.
Beaker Amount of Solute at Start (g) Amount of Solute at End (g)
Solution with Compound A 50 0 g
Solution with Compound B 50 15 g
Plain water in Beaker C 0 (control group) 0
Data Table 2
Record the the boiling point for each solution.
Beaker Temperature at Start (ºC) Temperature at Boiling Point (ºC)
Solution with Compound A 23 102.8
Solution with Compound B 23 108.7
Plain water in Beaker C 23 100
Analysis and Conclusion
1. Which compound dissolved more easily?
Compound A
2. Which compound had the lower boiling point?
Control C
3. Are the answers to 1 and 2 the same compound? What does this tell you about the strength of the bonds in this compound?
4. Which compound is the sugar?
5. Which compound is the salt?
Explanation:
