Nokea
In 1984, some drums of uranium hexafluoride were lost in the English Channel, which is known for its cold water (about 17°C). The melting point of uranium hexafluoride is 148°F. In what physical state is the uranium hexafluoride in these drums?
- A. solid
- B. liquid
- C. gas
- D. a mixture of solid and liquid
Correct Answer: A
Rationale: The correct answer is A: solid. Uranium hexafluoride has a melting point of 148°F, which is equivalent to approximately 64.4°C. Since the water temperature in the English Channel is only about 17°C, the uranium hexafluoride would be below its melting point and thus in a solid state. The other choices are incorrect because the temperature is not high enough for it to be in a liquid or gaseous state, and there is no indication of it being a mixture of solid and liquid based on the given information.
You may also like to solve these questions
A 0 mL sample of glycerol has a mass of 2 grams. What is the mass of a 57-mL sample of glycerol?
- A. 8.8 g
- B. 45 g
- C. 2.9 104 g
- D. 72 g
Correct Answer: B
Rationale: To find the mass of a 57-mL sample of glycerol, we use the given mass-to-volume ratio. Since 0 mL has a mass of 2 grams, the mass-to-volume ratio is 2g/0mL = 2g/mL. Therefore, for a 57-mL sample, we multiply 2g/mL by 57 mL to get 114 grams, which corresponds to answer choice B.
Choice A (8.8 g) is incorrect because it does not align with the calculated mass of 114 g for a 57-mL sample. Choices C (2.9 104 g) and D (72 g) are also incorrect as they are not consistent with the mass-to-volume ratio of 2g/mL provided in the question.
Which statement is not correct?
- A. The mass of an alpha particle is 7300 times that of the electron.
- B. An alpha particle has a 2+ charge.
- C. Three types of radioactive emission are gamma rays, beta rays, and alpha particles.
- D. A gamma ray is high-energy light.
Correct Answer: D
Rationale: The correct answer is D because gamma rays are not light but a form of electromagnetic radiation with high energy. Gamma rays have no charge and are produced from the nucleus. Choice A is correct as an alpha particle is heavier than an electron. Choice B is correct as an alpha particle has a 2+ charge. Choice C is correct as these are types of radioactive emissions.
How many significant figures are there in the number 0006428?
- A. 7
- B. 3
- C. 8
- D. 4
Correct Answer: D
Rationale: The correct answer is D: 4. Significant figures are non-zero digits and zeros between them. In this case, only digits 6, 4, 2, and 8 are non-zero, making them all significant. Zeros before the first non-zero digit are not significant, so the zeros before 6 are not counted. Hence, there are 4 significant figures in the number 0006428.
Choice A (7) is incorrect because it includes all digits, including the leading zeros, which are not significant. Choice B (3) is incorrect because it only considers the non-zero digits, excluding the zeros between them. Choice C (8) is incorrect because it counts all digits including leading zeros, which are not significant.
As warm water sits in a cool room, you measure the temperature change ( T = T – final T ). Which of the following is true? initial
- A. The temperature change ( T) is bigger if you are measuring in °F.
- B. The temperature change ( T) is bigger if you are measuring in °C.
- C. The temperature change ( T) will be the same regardless of the scale you use.
- D. Answer A or B is correct, depending on the difference in temperature between the water and the room.
Correct Answer: A
Rationale: The correct answer is A. When measuring temperature change, the size of the change will depend on the scale used. In Fahrenheit (°F), the scale has larger degrees compared to Celsius (°C). Therefore, the temperature change will appear bigger when measured in Fahrenheit. This is because each degree Fahrenheit is smaller in magnitude compared to each degree Celsius.
Choices B and C are incorrect. In choice B, the temperature change will not be bigger if measured in °C because each degree Celsius is larger in magnitude compared to each degree Fahrenheit. Choice C is incorrect because the temperature change does depend on the scale used.
Choice D is incorrect because the difference in temperature between the water and the room does not affect the scale used for measurement. The scale itself determines the magnitude of the temperature change.
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?
- A. 1.53 g/mL
- B. 5.11 g/mL
- C. 2.25 g/mL
- D. 0.196 g/mL
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