Chemistry HESI A2 Quizlet

Correct Answer: B

Rationale: The correct answer is B (-2). Group VIA elements, also known as Chalcogens, have 6 valence electrons. They typically gain 2 electrons to achieve a stable octet configuration, resulting in a -2 charge. Option A (-1) is incorrect because gaining 1 electron would not complete the octet. Option C (-3) is incorrect because gaining 3 electrons is energetically unfavorable. Option D (0) is incorrect because Group VIA elements tend to gain electrons to achieve stability.

Correct Answer: C

Rationale: The correct answer is C: Speeds up the reaction. A catalyst works by providing an alternative pathway for the reaction to occur with lower activation energy, thus increasing the reaction rate without being consumed in the process. This is achieved by stabilizing the transition state of the reaction, making it easier for the reactants to form products. Choice A is incorrect because a catalyst does not slow down the reaction. Choice B is incorrect as catalysts do have a significant effect on reaction rates. Choice D is incorrect because a catalyst does not stop the reaction; it only affects the rate at which the reaction occurs.

Correct Answer: D

Rationale: The correct answer is D because fluorine, oxygen, and nitrogen are typically involved in hydrogen bonding due to their high electronegativity, which allows them to form strong partial charges. This creates a polar covalent bond with hydrogen, leading to hydrogen bonding. Fluorine, chlorine, and oxygen (Choice B) are incorrect as chlorine is not typically involved. Carbon, hydrogen, and oxygen (Choice A) lack the necessary electronegativity for hydrogen bonding. Fluorine, chlorine, and nitrogen (Choice C) also lack the required electronegativity for effective hydrogen bonding. In summary, only elements with high electronegativity like fluorine, oxygen, and nitrogen are typically involved in hydrogen bonding.

Correct Answer: A

Rationale: The correct answer is A: Hydrogen and oxygen. Water decomposes into hydrogen and oxygen through a process called electrolysis. In this process, an electric current is passed through water, causing it to break down into its constituent elements. Hydrogen is produced at the cathode, while oxygen is produced at the anode. This is a well-known and scientifically proven reaction. Choices B, C, and D are incorrect because water does not decompose into carbon dioxide, nitrogen, or methane under normal conditions. This can be confirmed by studying the chemical properties and reactions of water.

Correct Answer: D

Rationale: The correct answer is D: Color of the reactants. The color of the reactants does not affect the reaction rate as it is a purely visual characteristic and does not influence the speed at which the reaction occurs. Temperature affects reaction rate by providing energy for molecules to react faster. Surface area influences reaction rate by increasing the area of contact between reactants. Concentration of reactants affects reaction rate by increasing the frequency of collisions between molecules. In summary, factors like temperature, surface area, and concentration directly impact reaction rate, whereas color is merely a visual property and does not play a role in determining the speed of a chemical reaction.