which of the following is an example of a weak acid

ATI TEAS 7

Mometrix TEAS 7 science practice test

1. Which of the following is an example of a weak acid?

A. Hydrochloric acid (HCl)
B. Sulfuric acid (H2SO4)
C. Acetic acid (CH3COOH)
D. Nitric acid (HNO3)

Correct answer: C

Rationale: The correct answer is Acetic acid (CH3COOH) because it is a weak acid that only partially dissociates in water, resulting in a lower concentration of H+ ions compared to strong acids like hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3) which completely dissociate in water. Weak acids do not fully ionize in water, leading to a lower concentration of H+ ions in solution. Hydrochloric acid, sulfuric acid, and nitric acid are strong acids that completely dissociate in water, producing a higher concentration of H+ ions. Therefore, they are not examples of weak acids.

2. What are the three layers of the heart?

A. Endocardium, myocardium, epicardium
B. Pericardium, endocardium, myocardium
C. Epicardium, myocardium, endocardium
D. Pericardium, myocardium, endocardium

Correct answer: C

Rationale: The correct answer is C: Epicardium, myocardium, endocardium. The heart wall consists of three layers: the outer layer is the epicardium, the middle muscular layer is the myocardium, and the inner layer is the endocardium. Understanding the layers of the heart is essential for comprehending its structure and function. Choices A, B, and D are incorrect because they do not present the layers of the heart in the correct order. The pericardium is the outermost layer that surrounds the heart, but it is not part of the heart wall itself. Therefore, choices B and D are incorrect. Choice A is incorrect as it presents the layers in the wrong order, starting with the endocardium instead of the epicardium, which is the outermost layer.

3. Which of the following characteristics is part of a person's genotype?

A. Brown eyes that appear hazel in the sunlight
B. The CFTR gene, which causes cystic fibrosis
C. Black hair that grows rapidly
D. Being a fast runner

Correct answer: B

Rationale: The correct answer is B. A genotype refers to a person's genetic makeup, which includes specific genes like the CFTR gene responsible for cystic fibrosis. Genes are the units of heredity and are part of an individual's genotype, influencing various traits and characteristics. Choice A, brown eyes that appear hazel in the sunlight, refers to a phenotype, which is the observable characteristics resulting from the interaction of genes and the environment. Choice C, black hair that grows rapidly, also describes a phenotype rather than a genotype. Choice D, being a fast runner, is a trait influenced by a combination of genetic and environmental factors, but it does not directly relate to a specific gene in the genotype.

4. What is the responsibility of the somatic nervous system?

A. Breathing
B. Thought
C. Movement
D. Fear

Correct answer: C

Rationale: The somatic nervous system is responsible for controlling voluntary movements of skeletal muscles. This system communicates sensory information and controls voluntary movements, such as walking or reaching for objects. Breathing is primarily regulated by the autonomic nervous system, which functions involuntarily. Thought processes involve complex interactions between various regions of the brain and are not directly controlled by the somatic nervous system. Fear is an emotional response that involves the limbic system of the brain and the autonomic nervous system, not the somatic nervous system.

5. When a person pushes a box across the floor, which of the following forces is NOT doing work?

A. The person's pushing force
B. The normal force from the floor
C. The gravitational force on the box
D. The frictional force between the box and the floor

Correct answer: B

Rationale: The normal force from the floor is perpendicular to the direction of motion of the box, so it does not contribute to the work being done. Work is only done by forces acting in the direction of motion of an object. In this case, the normal force is acting at a right angle to the motion, hence it does not perform any work on the box. The person's pushing force, the gravitational force, and the frictional force are all acting in the direction of motion of the box, so they contribute to the work being done in moving the box across the floor.