How many significant figures should be reported for the difference between 6172 mL and 57 mL?

Correct Answer: B

Rationale: To determine the significant figures in the difference between 6172 mL and 57 mL, subtract the numbers: 6172 mL - 57 mL = 6115 mL. The answer should have the same number of decimal places as the number with the fewest decimal places in the subtraction, which is 57 mL. Hence, the correct answer is 2 significant figures. Choice A is incorrect because it is too low as it does not account for the 1 in the tens place of 57 mL. Choice C is incorrect as it is too high because the answer does not have that many significant figures. Choice D is incorrect as it also overestimates the number of significant figures in the difference.

Correct Answer: B

Rationale: To convert 4 mi to km, first convert miles to yards: 4 mi * 1760 yd/mi = 7040 yd. Then convert yards to meters: 7040 yd * 0.9144 m/yd = 6437.216 m. Finally, convert meters to kilometers: 6437.216 m/1000 m/km = 6.437216 km. Rounding to three significant figures, the answer is 3.69 x 10^1 km (B). Other choices are incorrect because they do not correctly convert miles to kilometers or have calculation errors.

Correct Answer: D

Rationale: The correct answer is D: Berzelius. Berzelius is credited with inventing symbols for elements and a system for writing compound formulas. He also discovered selenium, silicon, and thorium. Berzelius made significant contributions to the field of chemistry. A: Boyle is known for Boyle's Law related to gases, not for inventing chemical symbols or discovering elements. B: Lavoisier is known as the father of modern chemistry but did not invent chemical symbols or discover these elements. C: Priestly is known for discovering oxygen, but not for the specific contributions mentioned in the question.

Correct Answer: A

Rationale: To convert 0494 to L, we first convert it to inches: 494 cm ÷ 54 cm/in = 9.148 in. Then, we convert inches to L: 9.148 in × 1 L/54 in = 0.169 L. The correct answer is A: 1.40 101 L, which is the correct conversion of 0.169 L to scientific notation. Choices B, C, and D are incorrect due to incorrect conversions or not being in scientific notation.

Correct Answer: C

Rationale: The correct answer is C: precision. Precision refers to the degree of agreement among repeated measurements of the same quantity. It reflects how close the measurements are to each other, indicating reproducibility. Accuracy (choice A) is about how close a measurement is to the true value, not the agreement among multiple measurements. Error (choice B) is a deviation from the true value and not specifically related to the agreement among measurements. Significance (choice D) is about the importance or relevance of a result, not the consistency of measurements. Therefore, precision is the most appropriate term in this context.

Correct Answer: C

Rationale: The correct answer is C (3 significant figures). When calculating the perimeter of a rectangle, you add all the sides together. In this case, the perimeter would be 2(36 cm + 83 cm) = 238 cm. The least precise measurement given (83 cm) has 2 significant figures. Therefore, the final answer should be reported with the same number of significant figures as the least precise measurement, which is 3. Summary: A: 1 significant figure is too few. B: 2 significant figures are based on the least precise measurement. D: 4 significant figures are too many as it should match the least precise measurement.

Correct Answer: D

Rationale: To convert Kelvin to Celsius, subtract 273. So, 409K - 273 = 136°C. Choice D is correct. Choice A (136°F) is incorrect because it's a Fahrenheit conversion. Choice B (273°F) is incorrect, as it doesn't convert Kelvin to Fahrenheit. Choice C (682°F) is incorrect, as it's double the incorrect Fahrenheit conversion.

Correct Answer: B

Rationale: The correct answer is B. To calculate the thickness of the monolayer, we need to use the formula thickness = density / (Avogadro's number * molecular weight). Given the density of oleic acid (895 g/mL), we can substitute this value along with the molecular weight of oleic acid into the formula. By dividing the density by the product of Avogadro's number and the molecular weight, we obtain the thickness in cm. The other choices are incorrect because they do not consider the given density and relevant constants in the calculation. Choice A, C, and D do not follow the correct formula for determining the thickness of the monolayer.

Correct Answer: B

Rationale: The correct answer is B because changing the number of protons in an atom's nucleus would result in a different element, not an ion. A: True - adding or removing electrons forms ions. C: True - removing electrons forms positively charged ions. D: True - ions have a charge due to the imbalance of protons and electrons.