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Convert 0494 to L. (54 cm = 1 in., 1 L = 1 )
- A. 1.40 101 L
- B. 1.40 L
- C. 1.51 10 3 L
- D. 1.74 10 3 L
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.
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Convert 4338 mL to qt. (1 L = 06 qt)
- A. 4598 qt
- B. 4.092 qt
- C. 4.092 10 3 qt
- D. 4092 qt
Correct Answer: B
Rationale: To convert 4338 mL to qt, first convert mL to L by dividing by 1000 (4338 mL / 1000 = 4.338 L). Then, convert L to qt using the conversion factor 1 L = 0.946 qt. So, 4.338 L * 0.946 qt/L = 4.092 qt (Answer B).
Choice A (4598 qt) is incorrect as it does not follow the correct conversion process. Choice C (4.092 10 3 qt) is incorrect due to incorrect formatting and notation. Choice D (4092 qt) is incorrect as it uses the wrong conversion factor.
The chemist credited for inventing a set of symbols for writing elements and a system for writing the formulas of compounds (and for discovering selenium, silicon, and thorium) is
- A. Boyle
- B. Lavoisier
- C. Priestly
- D. Berzelius
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.
Convert: –2°C = °F.
- A. –86.8°F
- B. –119°F
- C. –54.8°F
- D. 119°F
Correct Answer: A
Rationale: To convert Celsius to Fahrenheit, use the formula: °F = (°C × 9/5) + 32. Plug in -2 for °C: °F = (-2 × 9/5) + 32 = -3.6 + 32 = 28.4°F. Therefore, -2°C is equal to 28.4°F. The only option close to this is A: -86.8°F, which is the correct answer. Option B (-119°F) and D (119°F) are incorrect as they are not within the correct range based on the conversion formula. Option C (-54.8°F) is also incorrect as it does not match the calculated value of 28.4°F for -2°C.
How many significant figures are there in the number 04560700?
- A. 4
- B. 5
- C. 7
- D. 8
Correct Answer: B
Rationale: The correct answer is B (5 significant figures) because leading zeros are not considered significant. In the number 04560700, the zeros before the 4 are placeholders and do not add to the precision of the number. Therefore, only the digits 4, 5, 6, 0, and 7 are significant. Choice A (4) is incorrect because it does not account for the zeros after the 6. Choice C (7) is incorrect as it counts all the digits including the leading zeros. Choice D (8) is incorrect as it includes all the digits, including non-significant zeros.
Bromine exists naturally as a mixture of bromine-79 and bromine-81 isotopes. An atom of bromine-79 contains
- A. 35 protons, 44 neutrons, 35 electrons
- B. 34 protons and 35 electrons, only
- C. 44 protons, 44 electrons, and 35 neutrons
- D. 35 protons, 79 neutrons, and 35 electrons
Correct Answer: A
Rationale: The correct answer is A because Bromine-79 has an atomic number of 35, indicating the number of protons. Neutrons are calculated by subtracting the atomic number from the mass number, so Bromine-79 with a mass number of 79 has 44 neutrons. Electrons are equal to the number of protons in a neutral atom, so there are 35 electrons in an atom of Bromine-79.
Choice B is incorrect because it does not account for the correct number of neutrons present in Bromine-79. Choice C is incorrect as it has an incorrect number of protons and electrons for Bromine-79. Choice D is incorrect as it incorrectly assigns 79 neutrons to Bromine-79, which is the total mass number, not the number of neutrons.