Mometrix TEAS 7 science practice test

Correct Answer: B

Rationale: A) Incorrect. DNA is double-stranded, but RNA is typically single-stranded. B) Correct. DNA contains deoxyribose sugar, which lacks an oxygen atom on the 2' carbon of the sugar ring, while RNA contains ribose sugar, which has an additional hydroxyl group on the 2' carbon. C) Incorrect. RNA contains the nitrogenous base uracil, while DNA contains thymine. D) Incorrect. DNA and RNA have distinct structures and functions, so they are not identical molecules.

Correct Answer: C

Rationale: The pH of a solution can be calculated using the formula: pH = -log[H+]. Given that the hydrogen ion concentration is \(1 \times 10^{-9}\) M, the pH can be calculated as pH = -log(1 x 10^-9) = 9. Therefore, the correct answer is C) 9.

Correct Answer: B

Rationale: Sodium chloride (table salt) is typically a good conductor of electricity when dissolved in water because it dissociates into ions (sodium cations and chloride anions) that can carry an electric current. Sugar (choice A), olive oil (choice C), and oxygen gas (choice D) do not dissociate into ions in water and therefore are not good conductors of electricity. Sugar does not dissociate into ions in water, so it cannot conduct electricity. Olive oil and oxygen gas are nonpolar substances and do not ionize in water, making them poor conductors of electricity.

Correct Answer: B

Rationale: The energy of a wave is determined by its amplitude, which is the measure of its maximum displacement from the equilibrium position. Waves with higher amplitudes carry more energy as energy is directly proportional to amplitude. Therefore, the correct answer is B) Amplitude. Choice A (Wavelength) does not determine the energy of a wave; it is related to the spatial length between wave crests. Choice C (Frequency) is not the property that determines a wave's energy; it refers to the number of complete oscillations a wave undergoes in a given time. Choice D (Velocity) is the speed at which a wave propagates through a medium and is not directly related to its energy.

Correct Answer: D

Rationale: Beta waves, associated with alertness and focused attention, typically fall within the range of 13-30 Hz. These waves are present when individuals are engaged in cognitive tasks, problem-solving, or focused mental activities. Options A, B, and C are incorrect because these frequency ranges are not characteristic of beta waves. Beta waves are higher in frequency and are associated with more active mental states compared to the ranges mentioned in options A, B, and C. Therefore, the correct answer is 13-30 Hz (Choice D).