CHEM101L Lab 4 F

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CHEM101L

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Feb 20, 2024

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Lab 4 Molar Mass CHEM101L Student Name: Ani Harutyunyan Access Code (located on the lid of your lab kit): AC-ND9MT9 Lab Report Format Expecta0ons U"lize college level grammar and professional forma4ng when comple"ng this worksheet. Report all equa"ons in a proper mathema"cal format, with the correct signs and symbols. Pre-Lab Ques?ons 1. What are the units of molar mass? grams per mole(g/mol) 2. Chemists uClize the “mole” because it allows us to obtain the mass of an element or compound, and then know exactly how many atoms or molecules of that element or compound exist. Why do you think knowing the number of atoms or molecules is important? Balancing chemical equaCons is crucial for predicCng the outcomes of reacCons. 3. Note today’s date. Take that date and choose the atom in the periodic table corresponding to that date. For example, if today is July 20th, you would choose Calcium, since it has an atomic number of 20. Now, take the element you have chosen and calculate how many atoms you would have if you weighed out a 12 mg sample of that element. In your response, state today’s date, the element you chose and your answer. The date must match the Cmestamp of your lab, and you must show work for credit. Date: December 27, 2023 Element: Cobalt (Co) atomic number of element: 27 CalculaCon: 10 23 10 20 No. Of atoms: 1.226× 10 20 =12 mg of Co 4. Suppose you have one mole of an element. How many atoms would you have? What is another term for that number? Having one mole of any element means possessing approximately 6.022 x 10²³ atoms, a quanCty known as Avogadro's number, which helps link measurable quanCCes to the atomic scale in chemistry. 0.012 g /58.933 g / molx 6.022 x atoms / mol = 1.226 x atoms

Lab 4 Molar Mass CHEM101L EXPERIMENT 1: CALCULATING THE PERCENT SUGAR IN BUBBLEGUM Introduc?on Ques?ons 1. What steps will you be taking in this experiment? Why are you taking these steps? - Measure the weight of the bubblegum before chewing. -Chew the gum to extract the sugar. -Record the weight of the gum ader chewing. -Determine the sugar content by calculaCng the difference between the original and final weights. These steps are taken to calculate the sugar percentage in the bubblegum 2. The mass of the gum should decrease ader you chew it. Why? The weight of the gum reduces post-chewing due to the extracCon of sugar during the chewing process. 3. What might cause the mass to go up during the second reading? If the chewed gum absorbs moisture or saliva making the mass heavier. 4. What steps will you take to miCgate a higher, and thus false, mass reading? blogng the chewed gum to remove excess moisture before re-weighing can prevent false increases in mass reading. 5. Write the correct formula that you will use to calculate the percentage of sugar in this experiment. Percentage of sugar= Mass of dissolved sugar/mass of unchewed gum ×100 6. Why is Step 1 of the experimental procedure important? It establishes the iniCal mass of the bubblegum, which is essenCal for later calculaCng the sugar content ader chewing, as it provides a necessary baseline reference. 7. What acCon do you take in Step 3 of the experimental procedure? How would your data be negaCvely affected if you skipped this step? I'll reset the scale to 0.0 g between weighing the unchewed and chewed gum to ensure accurate measurement of sugar loss, as skipping this would lead to miscalculaCons by including the original gum's mass.

Lab 4 Molar Mass CHEM101L Data and Observa?ons Record the values you observe in the table below, along with the calculated value of the sugar content. Report these in units of grams. Other units will not be considered. Table 1: Sucrose (Sugar) Data Insert a photo of your chewed gum on your scale below, ensuring the mass reading on the scale, your handwrijen name, and the chewed gum are all visible. Important : To earn credit for this lab, the photo must show the mass reading on the scale corresponding to the value in Table 1. No credit will be awarded for this lab if they do not match. If you were unable to tear your scale according to the lab instrucCons, note the mass of the weigh-boat so that we may subtract that from the mass during validaCon of your data. Mass of gum before chewing (g) Mass of gum aQer chewing (g) Mass of sugar (g) 5.0 g 2.0 g 3.0 g

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Lab 4 Molar Mass CHEM101L Results and Discussion Important: QuesCons 1-6 below require calculaCons to be shown. The values used in those calculaCons must relate to the data you obtained. No credit will be provided for this lab in cases where the data does not agree with those in the observaCons, or where calculaCons are not shown. 1. What is the percent sugar? Show your calculaCons. Mass of sugar (g)-3.0 g Mass of unchewed gum (g)-5.0 g Percent sugar=mass of sugar/mass of unchewed gum x 100 percent sugar = 3.0g/1.0 g x 100 = 30% 2. What is the molar mass of sugar C 12 H 22 O 11 ? Show your calculaCons. Carbon (C): 12.01 g/mol Hydrogen (H): 1.01 g/mol Oxygen (O): 16.00 g/mol C 12 H 22 O 11 = C 12 H 22 O 11 The molar mass of sugar is 3. Convert the mass of dissolved sugar to moles. Show your calculaCons. Mass of sugar (g): 4.0 g Moles of Sugar= mass of sugar/molar mass of sugar moles of suga 4. Convert the moles of sugar to molecules of sugar. Show your calculaCons. Molecules of Sugar=Moles of Sugar×Avogadro’s Number Molecules of Sugar = 0.0278 moles × 6.022 x 10²³ molecules/mole Molecules of sugar ≈ 1.676 x10²³ molecules The number of sugar molecules is approximately 1.676 × 10²³ Imagine that you used four pieces of gum instead of two. Calculate the number of moles. Show your calculaCons. (12 × 12.01 g / mol ) + (22 × 1.01 g / mol ) + (11 × 16.00 g / mol ) = 144.12 g / mol 144.12 g / mol . r = 4.0 g /144.12 g / mol ≈ 0.0278 moles

Lab 4 Molar Mass CHEM101L Mass of sugar (g): 8.0 g Moles of Sugar (4 pcs) = Mass of Sugar Molar/Mass of Sugar Moles of Sugar (4 pcs) = Mass of Sugar/Molar Mass of Sugar Moles of Sugar (4 pcs) With four pieces of gum, there would be approximately 0.0556 moles of sugar. 5. How does the mass of the saliva alter the experimental data? Saliva absorpCon by chewed gum can falsely inﬂate the measured increase in mass, leading to an overesCmaCon of sugar mass, making it crucial to minimize saliva presence for accurate results. 6. Do you think this lab would work with sugar-free gum? If not, why? If so, how do you think the results would be different? This experiment, designed to measure sugar content by mass change before and ader chewing, may not be effecCve with sugar-free gum, as it contains no sugar and would likely show lijle to no change in mass. = 8.0 g /144.12 g / mol ≈ 0.0556 moles