balance the following redox reaction in acidic solution i aq cro aq i aq cr aq identify the oxidizing agent and reducing agent

ATI TEAS 7

TEAS 7 science practice

1. Balance the following redox reaction in acidic solution: I⁻ (aq) + Cr₂O₇²⁻ (aq) -> I₂ (aq) + Cr³⁺ (aq). Identify the oxidizing agent and reducing agent.

A. I⁻ is oxidized, Cr₂O₇²⁻ is reduced
B. I⁻ is reduced, Cr₂O₇²⁻ is oxidized
C. Both I⁻ and Cr₂O₇²⁻ are oxidized
D. Both I⁻ and Cr₂O₇²⁻ are reduced

Correct answer: B

Rationale: In the given redox reaction, I⁻ is gaining electrons to form I₂, which means I⁻ is being reduced (undergoing reduction). On the other hand, Cr₂O₇²⁻ is losing electrons to form Cr³⁺, indicating that Cr₂O₇²⁻ is being oxidized (undergoing oxidation). Therefore, I⁻ is the reducing agent and Cr₂O₇²⁻ is the oxidizing agent. Choice A is incorrect because I⁻ is being reduced, not oxidized. Choice C is incorrect as both species cannot be oxidized in the same reaction. Choice D is incorrect as both species cannot be reduced in the same reaction.

2. In a study where fish are fed different amounts of food daily for four weeks in separate tanks, with fish weight measured weekly, what is the dependent variable?

A. Weight of the fish
B. Type of food used
C. Number of fish tanks
D. Frequency of feedings

Correct answer: A

Rationale: The weight of the fish is the dependent variable in this study because it is the outcome being measured in response to the varying feeding amounts. The weight of the fish changes based on the feeding regimen, making it the dependent variable. The type of food used (choice B), number of fish tanks (choice C), and frequency of feedings (choice D) are not the dependent variables in this study. These factors may be independent variables that are manipulated or controlled in the experiment to observe their impact on the dependent variable, which is the weight of the fish.

3. What is correct about the hormones that stimulate male and female organs to produce male and female sex hormones?

A. Female organs are stimulated by female hormones and male organs by male hormones.
B. The same hormones that produce male or female sex characteristics stimulate the organs.
C. The same hormones stimulate both male and female organs to produce sex hormones.
D. The hypothalamus stimulates the pituitary gland's secretion of male and female hormones.

Correct answer: C

Rationale: The correct answer is C. The same hormones stimulate both male and female organs to produce sex hormones. Hormones such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are produced by the pituitary gland and act on the ovaries in females and the testes in males to stimulate the production of sex hormones (estrogen and progesterone in females, testosterone in males). Therefore, the same hormones stimulate both male and female organs to produce sex hormones. Choices A, B, and D are incorrect because they do not accurately describe the relationship between hormones and the stimulation of male and female organs to produce sex hormones.

4. What is the formula to calculate work?

A. Work = Force × Distance
B. Work = Mass × Velocity
C. Work = Power × Time
D. Work = Energy ÷ Time

Correct answer: A

Rationale: Work is defined as the product of the force applied to an object and the distance over which the force is applied. The formula to calculate work is represented by Work = Force × Distance, where force is the applied force on an object and distance is the displacement over which the force is applied. Therefore, the correct formula to calculate work is Work = Force × Distance. Choice B, 'Work = Mass × Velocity,' is incorrect because work involves force and distance, not mass and velocity. Choice C, 'Work = Power × Time,' is incorrect because work is not directly calculated using power and time. Choice D, 'Work = Energy ÷ Time,' is incorrect because work is not typically calculated by dividing energy by time; rather, it involves the product of force and distance.

5. What is the process of changing from a liquid to a gas called?

A. Freezing
B. Condensation
C. Vaporization
D. Sublimation

Correct answer: C

Rationale: The correct answer is C: Vaporization. Vaporization is the process by which a substance changes from a liquid state to a gas state. Choice A, Freezing, is incorrect as it refers to the process of changing from a liquid to a solid. Choice B, Condensation, is incorrect as it describes the process of changing from a gas to a liquid. Choice D, Sublimation, is incorrect as it involves changing directly from a solid to a gas without passing through the liquid state.