how many ml to the appropriate number of significant figures of a 0 m stock solution of hcl should be added to water to create 250 ml of a 50 m soluti

ATI TEAS 7

ATI TEAS Science Practice Test

1. How many mL of a 0 M stock solution of HCl should be added to water to create 250 mL of a 50 M solution of HCl?

A. 31.25 mL
B. 32 mL
C. 30 mL
D. 31.3 mL

Correct answer: B

Rationale: To prepare 250 mL of a 50 M solution of HCl, the formula V1 x C1 = V2 x C2 is used, where V1 is the volume of the stock solution, C1 is the concentration of the stock solution, V2 is the final volume of the desired solution, and C2 is the final concentration of the desired solution. Given V1 x 0 M = 250 mL x 50 M, solving for V1 results in V1 = (250 mL x 50 M) / 0 M = 32 mL. Therefore, 32 mL of the 0 M stock solution of HCl needs to be added to water to create a 250 mL solution of 50 M HCl. Choices A, C, and D are incorrect because they do not represent the accurate volume required for the dilution calculation based on the given concentrations and volumes in the problem.

2. What are energy levels and orbitals?

A. Energy levels are the paths that electrons travel around the nucleus of an atom, and orbitals are the regions where electrons are most likely to be found.
B. Energy levels are the regions where electrons are most likely to be found, and orbitals are the paths that electrons travel around the nucleus of an atom.
C. Energy levels are the same as orbitals.
D. Energy levels and orbitals do not exist.

Correct answer: A

Rationale: Energy levels refer to the specific energies that electrons in an atom can have, while orbitals are the regions within an atom where electrons are most likely to be found. Electrons do not travel in fixed paths around the nucleus like planets around the sun, as suggested in option B. Option C is incorrect because energy levels and orbitals are distinct concepts in atomic structure. Option D is incorrect as energy levels and orbitals are fundamental concepts in understanding the behavior of electrons in atoms.

3. What are the primary processes involved in breathing?

A. Inspiration and Expiration
B. Inhalation and Exhalation
C. Respiration and Circulation
D. Inspiration and Respiration

Correct answer: A

Rationale: The primary processes involved in breathing are inspiration (inhaling air) and expiration (exhaling air). Inspiration is the process of taking air into the lungs, while expiration is the process of expelling air from the lungs. These two phases are crucial for gas exchange, where oxygen is taken in during inspiration and carbon dioxide is expelled during expiration. Choices B, C, and D are incorrect as they either combine inspiration with respiration or include unrelated processes like respiration and circulation. Therefore, the correct pair of processes involved in breathing is A, inspiration and expiration.

4. What is the basic structure of an atom?

A. Protons, neutrons, electrons
B. Protons, electrons, ions
C. Neutrons, electrons, ions
D. Protons, ions, molecules

Correct answer: A

Rationale: The basic structure of an atom consists of protons and neutrons located in the nucleus, with electrons orbiting around the nucleus in specific energy levels or shells. Protons carry a positive charge, neutrons carry no charge, and electrons carry a negative charge. This arrangement maintains the overall neutrality of the atom, with the number of protons equaling the number of electrons. Therefore, the correct answer is 'Protons, neutrons, electrons.' Choices B, C, and D are incorrect as they do not accurately represent the fundamental components of an atom. Choice B includes 'ions,' which are charged particles, not fundamental components of an atom. Choice C includes 'ions' and lacks protons. Choice D includes 'ions' and 'molecules,' which are not part of the basic structure of an atom.

5. What property of a substance refers to its ability to be drawn into thin wires?

A. Conductivity
B. Ductility
C. Viscosity
D. Malleability

Correct answer: B

Rationale: Ductility is the property of a substance that allows it to be drawn into thin wires without breaking. Conductivity refers to the ability of a substance to conduct electricity or heat, not to be drawn into wires. Viscosity is the measure of a fluid's resistance to flow, not related to the ability to be drawn into wires. Malleability is the property of a substance that allows it to be hammered or rolled into thin sheets, not specifically related to being drawn into wires. Therefore, the correct property for the ability to be drawn into thin wires is ductility.