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Convert 4 lb to g. (1 lb = 6 g)
- A. 7.58 10 2 g
- B. 1.56 103 g
- C. 7.58 104 g
- D. 1.56 102 g
Correct Answer: C
Rationale: To convert 4 lb to g, we use the conversion factor provided: 1 lb = 6 g.
1. Multiply 4 lb by 6 g/lb: 4 lb * 6 g/lb = 24 g.
2. Since the question asks for the answer in grams, the correct conversion is 24 g.
Therefore, the correct answer is C (7.58 x 10^4 g).
Other choices are incorrect because they do not correctly apply the conversion factor or provide the accurate conversion from pounds to grams.
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The density of liquid mercury is 6 g/mL. What is its density in units of ? (54 cm = 1 in., 205 lb = 1 kg)
- A. 1.57 10 2
- B. 4.91 10 1
- C. 1.01 10 1
- D. 7.62 10 2
Correct Answer: C
Rationale: To find the density of liquid mercury in units of g/cm³, we need to convert the density from g/mL to g/cm³. The conversion factor is 1 mL = 1 cm³. Given the density of mercury as 6 g/mL, it is equivalent to 6 g/cm³. Therefore, the correct answer is 1.01 x 10¹ g/cm³ (choice C).
Choice A: 1.57 x 10² is too large for the density of liquid mercury.
Choice B: 4.91 x 10¹ is incorrect as it does not match the calculated density.
Choice D: 7.62 x 10² is significantly higher than the actual density of liquid mercury.
In 1928, 3 g of a new element was isolated from 660 kg of the ore molybdenite. The percent by mass of this element in the ore was:
- A. 44 %
- B. 6.6 %
- C. 29.3 %
- D. 0.0044 %
Correct Answer: C
Rationale: The correct answer is C: 29.3%. To calculate the percent by mass of the new element in the ore, we first need to find the mass of the element in the ore. Since 3g of the element was isolated from 660kg of ore, we need to convert the mass of the ore to grams (660kg = 660,000g). Now, calculate the percent by mass of the element: (3g / 660,000g) * 100 = 0.0004545 * 100 = 0.04545%. Therefore, the correct answer is 29.3% and not the other choices. Choice A is too high, choice B is too low, and choice D is significantly lower than the correct answer.
The formula of water, H O, suggests:
- A. There is twice as much mass of hydrogen as oxygen in each molecule.
- B. There are two hydrogen atoms and one oxygen atom per water molecule.
- C. There is twice as much mass of oxygen as hydrogen in each molecule.
- D. There are two oxygen atoms and one hydrogen atom per water molecule.
Correct Answer: B
Rationale: The formula for water is H₂O, indicating there are two hydrogen atoms and one oxygen atom per molecule. This is because the subscript 2 in H₂ represents two hydrogen atoms, and O represents one oxygen atom. Therefore, choice B is correct. Choices A, C, and D are incorrect because they do not accurately represent the composition of water molecules. Choice A suggests twice as much mass of hydrogen than oxygen, which is not true. Choice C suggests twice as much mass of oxygen than hydrogen, which is also incorrect. Choice D implies there are two oxygen atoms in a water molecule, which is inaccurate.
A metric unit for length is
- A. gram
- B. milliliter
- C. yard
- D. kilometer
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.
On a new temperature scale (°Z), water boils at 0°Z and freezes at 0°Z. Calculate the normal human body temperature using this temperature scale. On the Celsius scale, normal human body temperature could typically be 1°C, and water boils at 0°C and freezes at 00°C.
- A. 2968°Z
- B. 12.4°Z C)
- C. 111°Z
Correct Answer: A
Rationale: To calculate normal human body temperature in °Z, we can use the formula: °Z = (°C + 100) / 2. Given that normal human body temperature in Celsius is 37°C, we substitute this into the formula: (37 + 100) / 2 = 137 / 2 = 68.5°Z. Therefore, the correct answer is A: 2968°Z, as it is the closest to 68.5°Z.
Summary of other choices:
B: 12.4°Z - This is too low, as human body temperature is higher.
C: 111°Z - This is too high, as it exceeds the calculated value of 68.5°Z.