explain the law of conservation of mass as it applies to this reaction 2h o 2h o 2 2

ATI TEAS 7

ATI TEAS Science Practice Test

1. How does the Law of Conservation of Mass apply to this reaction: 2H₂ + O₂ → 2H₂O?

A. Electrons are not lost.
B. The hydrogen does not lose mass.
C. New water molecules are formed.
D. There is no decrease or increase in matter.

Correct answer: D

Rationale: The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. In the given reaction, 2 moles of hydrogen combine with 1 mole of oxygen to form 2 moles of water. The total mass of the reactants (hydrogen and oxygen) is equal to the total mass of the products (water), meaning there is no decrease or increase in matter. The total mass of the system remains constant, demonstrating the conservation of mass. Choices A, B, and C are incorrect because the conservation of mass does not specifically relate to electrons, individual elements (like hydrogen), or the formation of new molecules; instead, it focuses on the overall mass of the system before and after the reaction.

2. What is the medical term for a urinary tract infection (UTI)?

A. Nephritis
B. Cystitis
C. Urethritis
D. All of the above

Correct answer: B

Rationale: The medical term specifically used to refer to a urinary tract infection (UTI) that affects the bladder is cystitis. Nephritis refers to inflammation of the kidneys, and urethritis refers to inflammation of the urethra. As such, cystitis is the correct term for a UTI, making choice B the right answer. Choices A, C, and D are incorrect because they refer to different conditions affecting the urinary system.

3. What type of joint is found at the shoulder and hip, allowing for a wide range of motion?

A. Hinge joint
B. Ball-and-socket joint
C. Pivot joint
D. Saddle joint

Correct answer: B

Rationale: The correct answer is B: Ball-and-socket joint. A ball-and-socket joint, like the ones found at the shoulder and hip, allows for a wide range of motion. These joints provide multidirectional movement due to the rounded end of one bone fitting into the cup-like socket of another bone, enabling flexion, extension, abduction, adduction, and rotation. Choice A, Hinge joint, is incorrect because hinge joints allow movement in one plane, like a door hinge, and do not provide the wide range of motion seen at the shoulder and hip. Choice C, Pivot joint, is incorrect because pivot joints allow rotation around a single axis, such as the neck, and do not provide the same range of motion as ball-and-socket joints. Choice D, Saddle joint, is incorrect as saddle joints allow movement in multiple directions but are not as versatile or allow as wide a range of motion as ball-and-socket joints.

4. What is the path of oxygenated blood flow in our body?

A. From the heart directly to the brain
B. From the lungs to the left atrium, then to the left ventricle, and out through the aorta
C. From the body to the right atrium to the lungs
D. From the left atrium directly to the aorta

Correct answer: B

Rationale: Oxygenated blood flows from the lungs to the left atrium, then to the left ventricle, and is pumped out through the aorta to the body. This pathway ensures efficient oxygen delivery to the body's tissues and organs. Choice A is incorrect as oxygenated blood does not flow directly from the heart to the brain. Choice C is incorrect as it suggests a route from the body to the right atrium and then to the lungs, which is the pathway for deoxygenated blood. Choice D is incorrect as it describes a direct pathway from the left atrium to the aorta, skipping the left ventricle, which is essential for pumping blood to the body.

5. In the 18th century, women were more likely to die in childbirth compared to the 21st century. What is a possible explanation for why women are less likely to die in childbirth in the present age?

A. Doctors are better equipped to perform cesarean sections.
B. Doctors have more tools to monitor mothers during childbirth, enabling earlier detection of complications.
C. Doctors practice good hand hygiene to prevent the transfer of germs and infections.
D. All of the statements above provide reasonable explanations for the decrease in mortality during childbirth.

Correct answer: D

Rationale: All options are valid explanations for the decrease in maternal mortality during childbirth in modern times. Improved medical knowledge and technology have enabled doctors to perform cesarean sections more effectively, monitor mothers more closely for early detection of complications, and maintain better hygiene practices to reduce the risk of infections. Therefore, all the given statements collectively contribute to the reduction in maternal mortality rates in the 21st century.