Nokea
What is the pH of a solution with a pH of 7?
- A. Acidic
- B. Basic
- C. Neutral
- D. Positive
Correct Answer: C
Rationale: The correct answer is C: Neutral. A pH of 7 is considered neutral on the pH scale, which ranges from 0 to 14. A pH of 7 indicates a balance between acidic and basic properties in a solution, making it neither acidic nor basic. Values below 7 are acidic, above 7 are basic, and 7 is the midpoint representing neutrality. Therefore, a solution with a pH of 7 is neutral.
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What is the correct name for aqueous HI?
- A. hydroiodic acid
- B. hydrogen iodide
- C. iodine hydrogen
- D. hydroiodine acid
Correct Answer: A
Rationale: The correct name for aqueous HI is hydroiodic acid. In the naming of binary acids, the prefix 'hydro-' is combined with the root of the nonmetal element and the suffix '-ic acid'. Therefore, the correct systematic name for HI in aqueous solution is hydroiodic acid.
Which material has the smallest specific heat capacity?
- A. water
- B. wood
- C. aluminum
- D. glass
Correct Answer: C
Rationale: Specific heat capacity refers to the amount of heat energy needed to raise the temperature of a substance by a certain amount. In this context, aluminum has the smallest specific heat capacity among the materials listed. This means that aluminum requires the least amount of heat energy to increase its temperature compared to water, wood, and glass. As a result, aluminum is the material with the smallest specific heat capacity in this scenario.
What does carbonic acid become within the human body?
- A. Digests food
- B. Kills viruses
- C. Maintains pH of blood
- D. Grows hair
Correct Answer: C
Rationale: Carbonic acid, formed when carbon dioxide dissolves in water, plays a crucial role in maintaining the pH balance of the blood. It acts as a buffer to prevent drastic changes in blood pH, which is vital for the body's proper functioning. Carbonic acid does not digest food, kill viruses, or contribute to hair growth. Therefore, options A, B, and D are incorrect roles of carbonic acid within the human body, making maintaining the pH of blood (Option C) the correct answer.
What is the name of a reaction in which electrons are transferred from one atom to another?
- A. combustion reaction
- B. synthesis reaction
- C. redox reaction
- D. double-displacement reaction
Correct Answer: C
Rationale: A redox reaction, short for reduction-oxidation reaction, involves the transfer of electrons from one reactant to another. In these reactions, one substance is oxidized (loses electrons) while another is reduced (gains electrons). The term 'redox' comes from the simultaneous occurrence of reduction and oxidation reactions. Combustion reaction (choice A) involves a substance reacting with oxygen to produce heat and light, but it does not necessarily involve electron transfer. Synthesis reaction (choice B) involves the combination of two or more substances to form a new compound, with no mention of electron transfer. Double-displacement reaction (choice D) involves an exchange of ions between two compounds but does not specifically involve electron transfer between atoms. Therefore, option C, redox reaction, is the correct answer as it accurately describes the electron transfer process that occurs during such reactions.
What is the atomic number of a mystery element that has 6 protons, 6 electrons, and 6 neutrons?
- A. 6
- B. 12
- C. 18
- D. Not enough information
Correct Answer: A
Rationale: The atomic number of an element is equal to the number of protons in its nucleus. Since the mystery element has 6 protons, its atomic number is also 6. The number of neutrons and electrons does not affect the atomic number. Protons determine the element's identity, while neutrons and electrons affect its mass and charge, respectively. Therefore, choice A, 6, is the correct answer.