The cargo of uranium hexafluoride weighed kg and was contained in 30 drums, each containing L of UF . What is the density (g/mL) of uranium hexafluoride?

Correct Answer: C

Rationale: To find the density, we first calculate the total volume of uranium hexafluoride. Since each drum contains 15 L, the total volume is 30 drums * 15 L/drum = 450 L. Next, convert the mass from kg to g (1 kg = 1000 g). Density = mass/volume. Density = (mass in g) / (volume in mL). Since the mass is in g, we need to convert the volume from L to mL (1 L = 1000 mL). Density = (mass in g) / (volume in mL) = (mass in g) / (volume in L * 1000). Density = (mass in g) / (450 L * 1000) = (mass in g) / 450000 mL. Therefore, the density is the mass divided by 450000. The correct answer is C: 2.25 g/mL. Choice A is incorrect as it is too low

Correct Answer: D

Rationale: The correct answer is D: kilometer. A kilometer is a metric unit for length because it is used to measure long distances. In the metric system, length is typically measured in meters, and a kilometer is equal to 1000 meters. This makes it a suitable unit for measuring larger distances efficiently. Explanation for incorrect choices: A: Gram is a unit of mass, not length. B: Milliliter is a unit of volume, not length. C: Yard is a unit of length, but it is not a metric unit. The metric system uses meters and its derivatives for length measurements.

Correct Answer: D

Rationale: Rationale for correct answer D: Avogadro's hypothesis states that equal volumes of different gases at the same temperature and pressure contain an equal number of particles. This is because gases behave similarly under these conditions due to the ideal gas law. Avogadro's hypothesis is crucial in understanding the behavior of gases and is fundamental in the study of chemistry. Summary of incorrect choices: A: This statement is about the relative mass of atoms of different elements, not Avogadro's hypothesis. B: This statement relates to the law of definite proportions, not Avogadro's hypothesis. C: This statement refers to the law of multiple proportions, not Avogadro's hypothesis.

Correct Answer: C

Rationale: The correct answer is C: 6.7 x 10^8 mi/h. To calculate the speed of the electron in miles per hour, we first convert the speed of light from m/s to mi/h using the conversion factor 1 km = 6214 mi. The speed of light is approximately 6.71 x 10^8 mi/h. Since the electron is at 93% of the speed of light, we multiply the speed of light by 0.93 to get the speed of the electron, which is approximately 6.25 x 10^8 mi/h. The closest choice is C: 6.7 x 10^8 mi/h. Choice A: 2.8 x 10^8 mi/h - This is incorrect as it is too low compared to the calculated speed. Choice B: 6.2 x 10^11 mi/h - This is incorrect as it is too high compared to the calculated speed. Choice

Correct Answer: C

Rationale: To find the cost of a gram of gold at $1000 per troy ounce, we divide $1000 by 10 (since 1 troy ounce = 10g). This gives us $100 per gram. Therefore, the correct answer is C: between $10 and $50. Option A is incorrect as it is less than $1, option B is incorrect as it is between $1 and $10, and option D is incorrect as it is between $50 and $100.

Correct Answer: A

Rationale: The correct answer is A. Since the question states that there are 20 protons, option A with 22 protons is incorrect. Option B with 20 protons matches the given information, making it the correct answer. Option C with 18 electrons is unrelated to the given information about protons. Option D with just the number 22 is irrelevant and does not provide any information about protons.

Correct Answer: A

Rationale: The correct answer A is determined by knowing that the atomic number of rhenium is 75. Since the element is rhenium-185, the sum of protons and neutrons must equal 185. As the atomic number is 75, the number of protons is 75. Therefore, the number of neutrons is 185 - 75 = 110. Thus, rhenium-185 has 75 protons and 110 neutrons. Choices B, C, and D are incorrect as they do not adhere to the correct number of protons and neutrons in the nucleus of rhenium-185.

Correct Answer: A

Rationale: To convert 9 kg to lb, we multiply 9 kg by the conversion factor of 2.205 lb/kg. 9 kg * 2.205 lb/kg = 19.845 lb, which is approximately 20 lb. Among the choices, 17 lbs (option A) is the closest to 20 lb, making it the correct answer. Option B (1.7 lbs), C (3.6 lbs), and D (0.017 lbs) are all significantly lower and do not match the conversion calculation.

Correct Answer: C

Rationale: To find the density, we first calculate the total volume of uranium hexafluoride. Since each drum contains 15 L, the total volume is 30 drums * 15 L/drum = 450 L. Next, convert the mass from kg to g (1 kg = 1000 g). Density = mass/volume. Density = (mass in g) / (volume in mL). Since the mass is in g, we need to convert the volume from L to mL (1 L = 1000 mL). Density = (mass in g) / (volume in mL) = (mass in g) / (volume in L * 1000). Density = (mass in g) / (450 L * 1000) = (mass in g) / 450000 mL. Therefore, the density is the mass divided by 450000. The correct answer is C: 2.25 g/mL. Choice A is incorrect as it is too low