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CHEM-120 Unit 7 Lab Practicum Latest Updates 2024/2025
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CHEM-120 Unit 7 Lab Practicum Latest Updates 2024/2025
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CHEM-120 Unit 7 Lab Practicum LatestUpdates 2024/2025
freezing point of depression procedure + data collection ANS✔✔ - heated 3
different solutions (pure lauric acid, lauric acid and 0.4 g of benzoic acid,
lauric acid and 0.5 grams of benzoic acid
- determined freezing point of solutions
- used freezing point depression equation (delta Tf = molality*kf ) to
calculate molality of benzoic acid, then to molar mass of benzoic acid
freezing point of depression purpose + materials ANS✔✔ Lauric acid, benzoic
acid, test tubes, thermometer, beaker
-to determine the experimental molar mass of benzoic acid using the
colligative property freezing point depression
rates of chemical reactions procedure + data collection (activity 1) ANS✔✔
iodine clock reaction
1) calibration to determine how many drops of thiosulfate needed for each
reaction to be between 18-22 seconds
titrations lab materials + purpose ANS✔✔ to determine the concentration of
acetic acid in commercial vinegar using titration
vinegar samples (2), syringe, graduated cylinder, erlenmeyer flask,
phenophthalen indicator
characteristics of buffer solutions procedure ANS✔✔ -prepare 50 mL of 0.10
M sodium acetate (mass of sodium acetate from M calculations)
- prepare cups of pure water, acetic acid ( add universal indicator to make
pH colors stand out)
, -prepare 10 mL of 0.1M NaOH and HCl (dilution) and label and add indicator
-prepare 3.7, 4.7, 5.7 pH buffer solutions from preparation calculations
- add correct solutions to appropriate rows
- for part 2 pretty much the same but with dilution solutions of 4.7 pH buffer
rates of chemical reactions lab materials + purpose ANS✔✔ to determine the
effects of concentration, temperature, and addition of a catalyst on the rate
of reaction
used 24 well tray, pipets, cups, h2o2, KI, HCl, starch, sodium thiosulfate,
copper 2 sulfate, syringe
titrations procedure + data collection ANS✔✔ used a syringe to titrate 2
different vinegar samples with NaOH
- used the phenolphthalein indicator to know when the titration reaches it
endpoint
- recorded mass of 5 mL of vinegar in a graduated cylinder
-transfered to erlenmeyer flask and filled syring with NaOH
- added NaOH to vinegar in 0.5mL increments until color changed for a few
seconds, then by drops
- recorded volume of NaOH that it took to reach the endpoint
freezing point of depression how was freezing point determined ANS✔✔ -
melted lauric acid in a test tube in a hot water bath
-recorded temperature at 30s time intervals until freezing point was reached
(crystalized lauric acid)
- repeat with lauric acid and (2) benzoic acid amounts
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