Nokea
What is the oxidation state of the chlorine atom in the compound HCl?
- A. +1
- B. -1
- C. +2
- D. -2
Correct Answer: B
Rationale: In the compound HCl (hydrochloric acid), the hydrogen atom has an oxidation state of +1 based on the rules of assigning oxidation states. Since the overall compound is neutral, the oxidation state of chlorine must be -1 to balance the charge. Chlorine typically has an oxidation state of -1 in binary compounds with nonmetals, such as HCl. Therefore, the correct answer is -1. Choices A, C, and D are incorrect as the oxidation state of chlorine in HCl is -1, not +1, +2, or -2.
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What is the correct formula for silver hydroxide?
- A. AgO
- B. AgOH
- C. AgH
- D. AgHâ‚‚O
Correct Answer: B
Rationale: The correct formula for silver hydroxide is AgOH. Silver hydroxide is formed by the combination of the silver ion (Agâº) with the hydroxide ion (OHâ») to create AgOH. It is essential to note that the hydroxide ion consists of one oxygen and one hydrogen atom, thus the formula AgOH. Choices A, C, and D are incorrect as they do not accurately represent the composition of silver hydroxide.
What is the normal body temperature in Fahrenheit?
- A. 96°F
- B. 98.6°F
- C. 100°F
- D. 95°F
Correct Answer: B
Rationale: The normal body temperature for humans is 98.6°F, which is equivalent to 37°C. This temperature is considered the average baseline for most individuals when measured orally. Choice A (96°F) is too low for normal body temperature. Choice C (100°F) is too high for normal body temperature. Choice D (95°F) is also lower than the normal body temperature range. Therefore, the correct answer is B, 98.6°F.
Which of the following factors would not affect rates of reaction?
- A. Temperature
- B. Surface area
- C. Pressure
- D. Time
Correct Answer: D
Rationale: Time would not directly affect rates of reaction. The rate of a chemical reaction is determined by factors that affect the frequency of successful collisions between reactant molecules, leading to a reaction. Temperature, surface area, and pressure can influence reaction rates by impacting the kinetic energy of molecules, the exposed surface for collisions, and the concentration of reactants, respectively. However, time, in the context of this question, does not alter the rate of reaction but may affect the extent of the reaction or the amount of product formed over time.
If gas A has four times the molar mass of gas B, you would expect it to diffuse through a plug ___________.
- A. at half the rate of gas B
- B. at twice the rate of gas B
- C. at a quarter the rate of gas B
- D. at four times the rate of gas B
Correct Answer: A
Rationale: When comparing the diffusion rates of two gases, according to Graham's law of diffusion, the rate of diffusion is inversely proportional to the square root of the molar mass. If gas A has four times the molar mass of gas B, the square root of the molar masses ratio (4:1) is 2. This means that gas A would diffuse through a plug at half the rate of gas B. Therefore, the correct answer is A, at half the rate of gas B. Choices B, C, and D are incorrect because they do not reflect the correct relationship between the molar masses and the rates of diffusion according to Graham's law.
Which classification best describes B, Si, As, Te, At, Ge, and Sb that form a staircase pattern on the right side of the periodic table?
- A. Metals
- B. Semimetals
- C. Nonmetals
- D. Ultrametals
Correct Answer: B
Rationale: B, Si, As, Te, At, Ge, and Sb are located in a staircase pattern on the periodic table's right side. Elements in this region are known as metalloids or semimetals because they exhibit properties of both metals and nonmetals. They possess characteristics of both metallic and non-metallic elements, making them valuable semiconductors with diverse applications in electronics. Choice A is incorrect because these elements are not considered true metals. Choice C is incorrect as these elements do not display typical nonmetal properties exclusively. Choice D, 'Ultrametals,' is not a recognized classification in chemistry and is therefore incorrect.