End of Lab Questions 1/30/18 Lab 1, Part C, Day 2 1. a. What lab technique did you use to separate the ester from the impurities? Liquid-liquid extraction b. The water is more attracted to the unreacted alcohol and acid than to the ester. 2. a. Provide two pieces of evidence that you made isoamyl acetate (banana ester). Describe your evidence in adequate detail so a person who is familiar with this experiment can understand what you did. Evidence 1 = the product smells like banana so the smell matches the banana smell of isoamyl acetate. State the specific smell for full credit. Evidence 2 = IR spectrum. Match each peak to a bond type in isoamyl acetate. Look at the structure of isoamyl acetate. This compound has the following bond types: C-H bond stretch = 3000 cm -1. C-H bond bend = 1450 and 1375 cm -1. C-O bond stretch = 1100 cm -1. C=O bond stretch = 1700 cm -1. State the numerical value of each peak and correlate the peak to a specific bond type for full credit. If you see a IR peak between 3200 and 3500 cm -1, this peak represents an O-H bond. This could be due to water or alcohol or acid. b. Report your actu of ester. This actu is a mass in g. c. Report your % yield of ester. % yield = (actu/) x 100 of banana ester = 10 g 1/25/18 Lab 1, Part C, Day 1 1. a. State one item of data you collected in Part C. Data is a quantity you measured in an experiment. Mass or volume of isoamyl alcohol, volume of 17.4 M acetic acid, volume of H 2 SO 4, reaction time, actu of isoamyl acetate, IR peaks, smell of product. b. State one result you calculated in Part C. A result is calculated from data you collected. Moles of isoamyl alcohol, moles of acetic acid, % yield of isoamyl acetate, bond types (from IR peaks).
2. a. Give the chemical formula of the ester you made. Banana ester is isoamyl acetate = C 7. b. To make 5 g of the banana ester at 80% yield, calculate the mass of alcohol and acid needed. CH 3 COOH + C 5 O C 7 + H 2 O 5 g of the banana ester is the actu. Need to use the to calculate the amounts of reactants. % yield = (actu/) x 100 80% = (5 g/) x 100 = 6.25 g C 7 O 2 Alcohol name = isoamyl alcohol. Alcohol mass = 6.25 g C 7 x (1 mole/130 g C 7 ) x (1 mole C 5 O /1 mole C 7 ) x (88 g C 5 O/mole C 5 O) = 4.2 g C 5 O Acid name = acetic acid. Acid mass = 6.25 g C 7 x (1 mole/130 g C 7 ) x (1 mole CH 3 COOH /1 mole C 7 ) x (60 g CH 3 COOH/mole CH 3 COOH) = 2.9 g CH 3 COOH. 1/23/18 Lab 1, Part B 1. How is boiling water in a pot with the lid on like a reflux? Answer: As water boils, the water vapor comes in contact with the cooler lid, condenses back to a liquid, and drips back into the pot. 2. A liquid is heated in a reflux and distillation. The location of the determines where the vapor goes. Answer: Condenser or stopper. The adapter with the sidearm directs the vapor toward the condenser in a distillation so the vapor can condense into the receiving flask. If the condenser is attached directly to the reaction flask, the vapor that condenses drips back into the reaction flask. 3. a. In an IR spectrum, what wavenumber is an O-H bond observed? Answer: 3200-3500 cm -1 b. A peak at 1100 cm-1 indicates a bond. Answer: C-O single bond 1/18/18 Lab 1, Part A, Day 2 1. Identify the instrument you used to collect temperature data in Part A, Steps 1c and d. Answer: thermometer or temperature probe
A hot plate is a heating source; it does not measure temperature. Part A Conclusion. 2. a. What is the effect of temperature on your reaction? (As the temperature increases, what happens to the reaction rate?) Answer: in theory, the reaction occurs faster as the reaction temperature increases. b. Provide evidence to support your conclusion. More products should form in one minute for the faster reaction than the slow reaction. So the ester smell should be stronger after 1 minute for the faster reaction than the slower reaction. 3. a. What is the effect of the catalyst on your reaction? (As the amount of catalyst increases, what happens to the reaction rate?) Answer: in theory, the reaction rate should not change with the amount of catalyst. The reaction should be slower with no catalyst. If you tried the esterification reaction with no catalyst, it should be slower than the reaction with any amount of catalyst. b. Provide evidence to support your conclusion. More products should form in one minute for the faster reaction than the slow reaction. So the ester smell should be stronger after 1 minute for the faster reaction than the slower reaction. 4. Calculate the in g of the ester that you made. Reaction ROH RCCOH RCOOR 1 iso-amyl acetic iso-amyl acetate C5H11OH CH3COOH CH3COOC5H11 MW 88 60 130 drops 20 10 Volume 1 0.5 density 0.81 0.876 Concen, M 18 mass 0.81 1.17 moles 0.00920 0.009 0.009 2 ethanol acetic ethyl acetate C2H5OH CH3COOH CH3COC2H5 MW 46 60 88 drops 20 10 Volume 1 0.5 density 0.79 0.897 Concen, M 18
mass 0.79 0.792 moles 0.017 0.009 0.009 3 methanol salicylic methyl salicylate CH3OH C6H4(OH)(COO H) C6H4(OH)COOC H3 MW 32 138 152 drops 15 Volume 0.75 density 0.79 1.17 Concen, M mass 0.5925 0.1 0.110 moles 0.01852 0.00072 0.00072 4 ethanol propanoic ethyl propanoate C2H5OH C2H5COOH C2H5COOC2H5 MW 46 74 102 drops 15 20 Volume 0.75 1 density 0.79 0.99 0.88 Concen, M mass 0.5925 0.9900 1.3138 moles 0.0129 0.0134 0.0129 5 ethanol benzoic ethyl benzoate C2H5OH C6H5COOH C6H5COOC2H5 MW 46 122 150 drops 20 Volume 1 density 0.79 1.05 Concen, M mass 0.79 0.4 0.492 moles 0.01717 0.00328 0.00328 1/16/18 Lab 1, Part A, Day 1 b. Write the chemical formula of the ester produced from the acid and alcohol you used. Reaction 1 Reaction 2 Reaction 3 Reaction 4 Reaction 5
Alcohol iso-amyl alcohol ethanol methanol 15 drops ethanol 15 drops ethanol Alcohol formula C 5 H 11 OH C 2 H 5 OH CH 3 OH C 2 H 5 OH C 2 H 5 OH Acid acetic acid 10 drops acetic acid 10 drops salicylic acid 1 scoop (0.1 g) propanoic acid benzoic acid 1 scoop (0.4 g) Acid formula CH 3 COOH CH 3 COOH C 7 H 6 O 3 C 3 H 6 O 2 C 7 H 6 O 2 ester Iso-amyl acetate Ethyl acetate Methyl salicylate Ethyl propanoate Ethyl benzoate Ester formula C 7 O 2 C 4 H 8 O 2 C 8 H 8 O 3 C 5 H 10 O 2 C 9 H 10 O 2 Ester smell banana Fingernail polish remover (or fruity) wintergreen rum fruity