1.07 Option 2 Lab Techniques Final PDF

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1.07 Option 2 --Laboratory Techniques Lab Report

Intermolecular Strength Hands-on Lab Instructions: For this investigative phenomenon, compare the intermolecular strengths of two substances by comparing their boiling points. Intermolecular strength refers to the force of attraction between atoms or molecules within a substance. Substances with stronger attractions between molecules will need more kinetic energy to overcome these attractive forces. The heating of a substance is the transfer of thermal energy to kinetic energy within molecules. Record your observations and test measurements in the lab report below. You will submit your completed report. Title:

Intermolecular strength between Apple juice and Almond Milk

Objective(s): Compare which of the two substances has a higher boiling point Compare which of the two substance boils faster

Hypothesis: Make a prediction about the intermolecular strengths of the two substances you plan to test. How is the boiling point of a substance influenced by intermolecular forces? I predict that apple juice has stronger intermolecular forces, therefore a higher boiling point, than milk.

Procedure: Materials: Milk Apple Juice Two pots thermometer

measuring cup stove Variables: The controlled variables are the heat source, thermometer, container type, volume of liquid, and the boiling point of water (100 or 212 ) The Independent variable: (the variable we are changing) is the type of liquid heated. The dependent variable (the variable that changes due to the independent variable) is the boiling point of each liquid Summary of Steps Step 1: Select two safe substances to boil. Make sure to list the units used to measure your substance when recording your volumes in the data chart. Step 2: Measure said substances. ½ cups of each and pour into heating container Step 3: Submerge the tip of your thermometer into your substance and record the starting temperature in the temperature data chart. Step 4: Set heat to medium, and record starting temperature Step 5: Place heating container to stove top Step 6: Record the temperature of your substance at set time intervals. Intervals for measurement are every two minutes, depending on the setting of your heat source. Step 7: Record these values in the data table. Step 8: Once your substance has reached a boil, take additional temperature measurements before removing it from the heat. Step 9: Record the volume and boiling point of your substance in the boiling point data chart. Step 10: Repeat two more times

Data: Type the results of your tests in the data table below. Don't forget to record measurements with the correct number of significant figures. Hint: Using the same instrument, you should have the same number of digits to the right of the decimal (all masses, then all volumes, etc.). Temperatures Data Select the time intervals for your experiment (1 minute, 2 minutes). Replace the Time 1, 2, 3 with these values. Add more columns for time if needed. List the temperatures of the substances while heating at each of these intervals. . Trial 1

2 min

4 mins

6 mins

8 mins

10 mins

12 mins

14 mins

Substance 1 Apple Juice Substance 2 Milk

80 F

87 F

93 F

105

120

130

79 F

85 F

97 F

110 F

135 F

Trial 2

2 min

4 mins

6 mins

8 mins

Substance 1 Apple Juice Substance 2 Milk

82 F

85 F

94 F

81 F

86 F

Time 1 79 F

83 F

Trial 3 Substance Apple Juice Substance Milk

16 min

18 min

145

160

160

150 F

180 F

203

203

10 mins

12 mins

14 mins

16 min

107 F

119 F

130 F

156 F

160 F

160 F

95 F

112 F

137 F

157 F

198 F

203 F

203 F

Time 2 83 F

Time 3 89 F

Time 4 105

Time 5 118 F

Time 6 131 F

Time 7 154 F

Time Time 8 9 160 F 160 F

88 F

97 F

115 F

140 F

163 F

181 F

203 F

18 min

203 F

Boiling Point Data Part I: Boiling Point of Substance 1 APPLE JUICE

Trial 1

Trial 2

Trial 3

Volume of liquid (unit of measurement?)

1 CUP

1/2 CUP

1/2 CUP

Boiling point of substance (Fahrenheit or Celsius?)

160

160

160

Volume of liquid (unit of measurement?)

1 CUP

1/2 CUP

1/2 CUP

Boiling point of substance (Fahrenheit or Celsius?)

203

203

203

Part II: Boiling Point of Substance 2 MILK

Conclusion: Write a conclusion statement that addresses the following questions: For this lab, I predicted that apple juice would have stronger intermolecular forces and a higher boiling point compared to apple juice. The data did not support my hypothesis. Apple juice had the lower boiling point at 160 , compared to milk at 203 ; therefore, it has weaker intermolecular forces between its molecules. These boiling points are less than that of water. Substances with stronger attractions between molecules will need more heat to overcome these attractive forces and cause the liquid to boil. To further investigate this phenomenon, more substances could be heated to compare their boiling points to those of milk and apple juice to make more inferences regarding intermolecular forces.

Post Lab Reflection Questions: Answer the reflection questions using what you have learned from the lesson and your experimental data. It will be helpful to refer to your chemistry journal notes. Answer in complete sentences.

1. How would you determine the proper number of significant figures for the volume of liquid using your measuring equipment? For example, if you used a kitchen measuring cup with measurement intervals on the side, how would you report the measurement in the correct number of significant figures? Precision refers to the consistency of a group of measurements taken in the same way on the same amount. I measured the boiling point of a liquid in this experiment using the same thermometer, the same units, and the same conditions in several trials 2. Are the boiling point temperatures for both substances precise and accurate? Explain your answers. The boiling point for both substances are precise and accurate since I repeated the experiment multiple times and got the same temperature. 3. Why were the substances you selected appropriate for investigating the strength of intermolecular forces? (Hint: compare the compositions of your substances and describe any patterns you observe) The selected substances were appropriate for investigating the strength of intermolecular forces because they differ in boiling point which helps determine the intermolecular forces. 4. Using your knowledge of boiling points and intermolecular forces, why do you think rubbing alcohol dries so quickly from your skin? (Hint: use the patterns you observe in properties to help explain this) Rubbing alcohol most likely has a low boiling point and weak intermolecular force....