Aniya Mims Lab manual lab#1 sugar

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City Colleges of Chicago, Malcolm X *

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121

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Chemistry

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Feb 20, 2024

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pdf

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Lab#1 remote v1 1 Lab 1: Scientific Method with Sugars A. Learning Objectives Identify probable factors that contribute to variations among individuals. Differentiate independent, and control dependent variables. Articulate hypotheses that state the relationship between independent and dependent variables. Design an experiment to test the stated hypothesis. Record, tabulate, graph and interpret collected data. B. Materials List Item Quantity 1 Granulated table sugar 1/2 cup = 4 oz. = 120 mL 2 Tap water 1 cup = 240 mL 3 Vinegar (optional) 1/3 cup 4 Spoon 3 counts 5 8 oz. or larger glass, bowl or disposable cup 3 equal size containers 6 Stop watch in your phone 1 7 Measurement tools – cup, teaspoon, table spoon or graduated cylinder (one in the lab kit) 1 each 8 Optional: thermometer, pH test strip C. Research question: What factors could affect how fast sugar dissolves in water? The factors that could affect how fast sugar dissolves in water would be temperature, particle size, concentration of sugar, type of sugar, and type of water.

Lab#1 remote v1 2 D. Design an experiment to answer the above research question. Pick one “factor” in you answer to C that you wish to research in this lab. One “ factor ” in my answer to C that I wish to research in this lab would be temperature. Your independent variable = temperature of the water; dependent variable = time it takes for the sugar to dissolve Write your hypothesis in the space below. Hint: Must state the relationship between the independent and dependent variable. As the temperature of the water increases, the time it takes for the sugar to dissolve will decrease. Draw a graph to show what you expect to see in the data you ’re going to collect BASED on your hypothesis in the box below. DO NOT use the actual data you collect. Plot a scatter graph, Y (= dependent variable) vs. X (=independent variable), and show the trendline. Now “design” an experiment to test your hypothesis. Write down the procedure in the box below. Hints – (a) you’d want to vary your independent variable and measure the dependent variable to see whether there is any relationship between the independent and dependent variable. (b) To make sense of the data, it is advisable to use at least THREE different values of the independent variable. (c) Finally, a good experiment must keep every other factor, except the chosen independent variable, constant (unchanged). These “other” factors are also called control variables because they must be “controlled” (and stay constant). 0 2 4 6 8 10 12 0 1 2 3 4 5 Time it Takes for the Water to Dissolve (seconds) Temperature of the Water (degrees C) Effect of Water Temperature on the Rate of Sugar Dissolution

Lab#1 remote v1 3 1. Put ½ cup of granulated table sugar in 3 different cups for each trial. 2. Put 1 cup of tap water in 3 different cups for each trial. 3. Label one cup of tap water as “ cold ” , another cup as ‘ room temperature ” and the last one as “ hot ” . Fill the cup with “ hot ” water from a heated source (microwave), the “ room temperature ” water from the tap, and the “ cold ” water from the refrigerator. 4. Measure and record the initial temperature of each cup of water. 5. Add the sugar to each cup of water at the same time. 6. Start the timer as soon as the sugar is added. 7. Stir each cup with the mixture of sugar for one minute using a spoon. 8. Observe and record the time it takes for the sugar to dissolve completely in each cup. Ensure accuracy by stopping the timer as soon as no visible sugar particles are present. 9. Repeat the experiment for each temperature condition at least 3 times for accuracy. 10. Calculate the average time for sugar dissolution at each temperature. Compare the average time to identify any trends or patterns. E. Experimental data Record data in this following table - Trial # Average Temperatures of the Water (in degrees Celsius) Average Time it Takes for the Sugar to Dissolve (in seconds) 1 10 16 2 25 9 3 90 3 F. Display your data in a graph below Please use Excel to plot your data and paste your graph here for the final report. You could also draw the graph by hand, take a picture of the graph, email the picture to yourself and paste that picture here OR upload pictures to Brightspace separately if the file becomes too big. Use a lower “resolution” to reduce the file size of your picture. Otherwise, Brightspace may reject your picture. Picture files must be in .jpg, .pdf, or .tiff

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Lab#1 remote v1 4 G. Summarize your results: The time it takes for sugar to dissolve appears to decrease as the temperature of the water increases. Trial 1, Trial 2, and Trial 3 consistently show shorter dissolution times for the “ hot ” water compared to “ room temperature ” and “ cold ” water. The “ cold ” water consistently has longer dissolution times across all three trials. All in all, the trends from the table & graph support the initial hypothesis that higher water temperatures lead to faster sugar dissolution. H. Post Lab Discussion – Your hypothesis may or may not agree with your results. If not, you would need to reconcile these two differences. Based on prior knowledge, issues you encounter during the lab and your own research, provide evidences to support either your hypothesis OR results. Furthermore, even if your hypothesis agrees with your results, that is not sufficient to assert that your hypothesis is absolutely correct or the experiment is done correctly. This is where research on laws of physics/chemistry, prior knowledge and your reflection of whether you’ve successfully controlled other variables are important. If your results and hypothesis DO NOT agree, answer this question. Otherwise skip to 2. Which one, the hypothesis or results, makes more sense? Why? Now, apply the deduction reasoning, i.e use the general rules in chemistry and/or physics, to support your statement. DO NOT USE your pre-lab observation to answer this question. 1 3 5 7 9 11 13 15 17 19 012345678910 112 13 14 15 16 17 18 19 20 21 223 24 25 26 27 28 29 30 31 32 334 35 36 37 38 39 40 41 42 43 445 46 47 48 49 50 51 52 53 54 556 57 58 59 60 61 62 63 64 65 667 68 69 70 71 72 73 74 75 76 778 79 80 81 82 83 84 85 86 87 8890 91 92 93 94 95 96 97 98 99 100 Average Time it Takes for the Sugar to Dissolve (in seconds) Average Temperature of the Water (in degrees Celsius) "Effect of Water Temperature on the Rate of Sugar Dissolution"

Lab#1 remote v1 5 If your results DO agree with the hypothesis, You developed your hypothesis based on an initial observation. Now your result agrees with your hypothesis. How do we know that your result and/or hypothesis is real (not just luck)? Now, apply the deduction reasoning, i.e. use the general rules in chemistry and/or physics, to support your statement. DO NOT USE your pre-lab observation to answer this question We know that the result and/or hypothesis is real (not just luck) because it is supported by the fundamental principles of solubility and kinetic molecular theory. The solubility principles state that higher temperatures lead to increased solubility for many substances. This is observed in the experiment where the sugar in the “hot” water was able to be dissolved faster than the other water temperatures. The Kinetic Molecular Theory states as the temperature increases, the kinetic energy of molecules increase as well. This can be seen when the “ hot ” water (solvent) and sugar (solute) were combined in the cup causing an increase in energetic collisions leading to a faster dissolution process. List two control variables that you did well and describe what you did. (Do not discuss dependent or independent variable. Please review what control variables mean) List two control variables that you did NOT do well and describe how these mistakes could have impacted your results. (Do not discuss dependent or independent variable. Please review what control variables mean.) Two control variables that I did not do well were the cup shape and the atmospheric pressure. These mistakes could have impacted my results because the cups being different shapes could have compacted the surface area of the water exposed to the surroundings. It also could’ve impacted my results because the change in the atmospheric pressure can affect the boiling point and evaporation rates of water. The two control variables that did well would be type and amount of sugar and stirring method and duration. This went well because I used the same granulated sugar for each trial and the same amount of sugar (1/2 cup). It also went well because I used the same spoon to stir the sugar and stirred it for the same amount of time.