Lab 1 Floating Egg Lab - First lab PDF

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Floating Eggs: Lab 1 Xavier Valencia Section: 2A38 10/12/2018 Introduction: Density measures how tightly packed an object is. Water’s density is 1g/cm3, meaning that for every cm3 there is one gram of water. The average density of an egg is about 1.06g/cm3 meaning that would sink due to the density being greater than the water. Archimedes’ Principle states that “an object immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid”1 The buoyant fluids depend on the displaced liquid not the object weight itself. density equals mass divided by the volume. (D = M/V). Egg contains proteins, vitamins and other elements that factor into the density. The egg’s density is larger than the density of water. In the lab we’ll be determining the density of the egg through two experiments. The first experiment used to determine the volume of two eggs (labeled A and B) will be conducted by adding salt, which changes the mass of the water but not the volume, until the egg floats. The calculated density of the salt water used to float the egg would theoretically equal to the density of the egg. The second experiment takes the weight of both eggs and divides it by volume of the egg, which is displaced by the displaced water in a volumetric cylinder after the egg is dropped in. Experimental: Procedure: (found in Green Lab Manual “General Chemistry Lab Manual”) Original Procedure: Fill 400 mL beaker to 300mL with H 2O Altered Procedure: Fill 1000 mL volumetric cylinder with 300mL with H 2O Original Procedure: Drop egg into 500 mL of water Record the displaced water level Repeat four times Altered Procedure: Drop egg into 500 mL of water Record the displaced water level Repeat five times (to remove outliers)

Data Analysis:

1 General Chemistry Lab Manual

Initial Weight of Salt and Volume of Water Trial*

Water Volume

Initial Dish Weight

Dish + Salt Weight

Salt Weight

1A

301 mL

5.58 g

77.42 g

71.84 g

2A

299 mL

5.58 g

74.68 g

69.10 g

3A

298 mL

5.58 g

77.07 g

71.49 g

4A

302 mL

5.58 g

73.79 g

68.21 g

1B**

298 mL**

5.42 g**

76.34 g**

70.92 g**

2B

299 mL

5.42 g

79.08 g

73.66 g

3B

298 mL

5.42 g

78.28 g

72.86 g

4B

295 mL

5.42 g

77.22 g

71.80 g

5B

301 mL

5.42 g

78.37 g

72.95 g

* Trial 1A indicates the first trial of egg ‘A’, 1B applies to trial of egg ‘B’ **--- Strikethrough outlier data, not apart of final calculations Salt Used to Float Egg Trial

Initial Salt Weight

Final Salt Weight

Used Salt Weight

1A

71.84 g

33.28 g

(71.84 - 33.28) = 38.56 g

2A

69.10 g

31.83 g

(69.10 - 31.83) = 37.27 g

3A

71.49 g

35.05 g

(71.49 - 35.05) = 36.44 g

4A

68.21 g

29.23 g

(68.21 - 29.23) = 38.98 g

1B

70.92 g

51.70 g

(70.92 - 51.70) = 19.22 g

2B

73.66 g

58.17 g

(73.66 - 58.17) = 15.49 g

3B

72.86 g

57.85 g

(72.86 - 57.85) = 15.01 g

4B

71.80 g

56.83 g

(71.80 - 56.83) = 14.97 g

5B

72.95 g

55.53 g

(72.95 - 55.53) = 15. 42 g

Density of Eggs as Determined by Salt Water Density Trial

Salt Weight

Weight of Water*

Weight of Salt Water

Density Calculations (g/mL)

Density of Eggs

1A

38.56 g

301 g

339.56 g

(339.56/301)

1.13 g/mL

2A

37.27 g

299 g

336.27 g

(336.27/299)

1.12 g/mL

3A

36.44 g

298 g

334.44 g

(334.44/298)

1.12 g/mL

4A

38.98 g

302 g

340.98 g

(340.98/302)

1.13 g/mL

1B

19.22 g

298 g

317.22 g

(317.22/298)

1.06 g/mL

2B

15.49 g

299 g

314.59 g

(314.59/299)

1.05 g/mL

3B

15.01 g

298 g

313.01 g

(313.01/298)

1.05 g/mL

4B

14.97 g

295 g

309.97 g

(309.97/295)

1.05 g/mL

5B

15.42 g

301 g

316.42 g

(316.42/301)

1.05 g/mL

* The weight of the water is assumed from the volume of the water. Since the density of water is 1.00g/mL, one mL of water is equal to one gram of water

Mean and Standard Deviation of Egg ‘A’ and ‘B’ Egg A

Mean Calculation

Mean

(1.13 + 1.12 + 1.12 + 1.13)

Standard Deviation Calculation

1.13 g/mL (1.13 - 1.13)2 +(1.12 - 1.13)2 +(1.12 - 1.13)2 +(1.13 - 1.13)2 3

4 (1.05 + 1.05 + 1.05 + 1.05)

1.05 g/mL (1.05 - 1.05)2 +(1.05 - 1.05)2 +(1.05 - 1.05)2 +(1.05 - 1.05)2

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3

4

Density of Eggs Determined by Weight and Volume Trial

±0.0001

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B

STD

Egg

Initial

Final

Volume of

Density Calculations

Density of

±0

Weight

Volume Water

Volume Water

Egg

(g/mL)

Eggs

1A

69.61 g

620 mL

685 mL

65 mL

(69.61/65)

1.09 g/mL

2A

69.61 g

673 mL

738 mL

65 mL

(69.61/65)

1.09 g/mL

3A

69.61 g

635 mL

700 mL

65 mL

(69.61/65)

1.07 g/mL

4A

69.61 g

579 mL

643 mL

64 mL

(69.61/64)

1.09 g/mL

1B

63.91g

509 mL

570 mL

61 mL

(63.91/61)

1.05 g/mL

2B

63.91 g

616 mL

678 mL

62 mL

(63.91/62)

1.03 g/mL

3B

63.91 g

628 mL

690 mL

62 mL

(63.91/62)

1.03 g/mL

4B

63.91 g

641 mL

704 mL

63 mL

(63.91/63)

1.01 g/mL

5B

63.91 g

673 mL

735 mL

62 mL

(63.91/62)

1.03 g/mL

Mean and Standard Deviation of Egg ‘A’ and ‘B’ Egg A

Mean Calculation (1.09 + 1.09 + 1.07 + 1.09) --------------------------------------------------

4 B

(1.03 + 1.03 + 1.01 + 1.03) -------------------------------------------------

4

Mean

Standard Deviation Calculation

1.09 g/mL (1.09 - 1.09)2 +(1.09 - 1.09)2 +(1.07 - 1.09)2 +(1.09 - 1.09)2

STD ±0.0001

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3 1.03 g/mL (1.03 - 1.03)2 +(1.03 - 1.03)2 +(1.01 - 1.03)2 +(1.03 - 1.03)2 ---------------------------------------------------------------------------------------------------------

3

Discussion: My results from the lab, at least the one that resulted from the experiment where the density is derived from the water density at which the egg floated appears to be inaccurate (Egg ‘A’ = 1.13±0.0001 g/mL and Egg ‘B’ = 1.05±0.0 g/mL). The results from the experiment derived from weighing and determining the volume by the displaced water seems to be more accurate

±0.0001

(Egg ‘A’ = 1.09±0.0001 g/mL and Egg ‘B’ = 1.03±0.0001 g/mL). Although the standard deviation values are low, indicating high precision, the accuracy in relation to each other seems less than ideal. The densities as determined by weight seem to be more accurate as they come from straightforward measurements (weight and volume). However, the reason to be skeptical of the mass determined by the salt water density derives from drawn out experimentation that can include many experimental errors along the way. Although there seems to be no definitive answer on the density of eggs due to the variations of eggs found throughout the world there is a general consensus online that dictates that boiled eggs have a smaller density than raw eggs. From this we can determine that our experiments were accurate in dictating that the raw egg has a higher density than the boiled egg. Some possible errors that can be improved upon in the future revolves around the experiment with the salt water density. One would be understanding to which lab calls for the egg to float. Both students that conducted and gathered the data had a breaking of the water surface. This error could have led to an over assumption of the egg’s density due to the fact that if the egg floated it would indicate that the density was less than the salt water’s density. Paying closer attention and drawing the line at whether to put a little more salt or not could have improved the accuracy of the lab, from the salt water density standpoint. Post Lab Discussion: 3. The results from salt water density experiment (Egg ‘A’ = 1.13±0.0001 g/mL and Egg ‘B’ = 1.05±0.0 g/mL) and the results from the mass and volume experiment (Egg ‘A’ = 1.09±0.0001 g/mL and Egg ‘B’ = 1.03±0.0001 g/mL) differ from one another. The results from the salt water density experiment are higher than the other experiment, most likely due to the over dissolving of salt, arising from experimental errors. 4. Experiment 2 seems to be more accurate as it come from two straightforward calculations, the mass of the egg and the volume of the egg. Experiment one, perhaps done accurately could be accurate, but the experiments performed on this lab seem to indicate that experiment 1 is not accurate. 5. In both experiments Egg ‘A’ the raw egg is the denser of the two eggs, making egg ‘B’, the boiled egg, less dense. Assuming that both experiments are accurate enough it can be determined that the boiled egg is less dense than the raw egg. 6a. No, both eggs would not have similar or same densities. Both experiments indicate that the raw egg’s density (on average of both experiment A and B) is 0.07±.0002 greater than egg B. b. Aside from cracking the egg open to determine whether the egg is boiled or raw, spinning the egg will give an indication whether the egg is boiled or raw. By spinning a raw egg you observe that the egg does not spin well, toppling over almost immediately. The lack of spin comes from the free flowing liquid (the yolk and egg whites) within the raw egg. The boiled egg, when spinned, spins like a top for a while, enough to distinguish the difference between the two eggs. The egg comes from the uniform egg inside. After boiling the egg and denaturing the proteins the egg takes the full space of the egg, leaving no extra weight to throw off the spin.

c. (20.4g NaCl + 10.62g sugar + 500.8g H2O) = 531.82g 531.82 g -------------- = 1.062 g/mL Sugar/Salt Water Solution 500.8 mL...