how do isotopes affect the atomic mass of an element

ATI TEAS 7

TEAS 7 science practice

1. How do isotopes affect the atomic mass of an element?

A. Isotopes have no effect on the atomic mass of an element.
B. Isotopes cause the atomic mass of an element to vary slightly.
C. Isotopes cause the atomic mass of an element to be exactly the same for all isotopes of that element.
D. Isotopes cause the atomic mass of an element to vary greatly.

Correct answer: B

Rationale: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. Since the atomic mass of an element is the weighted average of the masses of its isotopes, the presence of isotopes causes the atomic mass of an element to vary slightly. This variation occurs because different isotopes have different masses due to their varying numbers of neutrons. The atomic mass is affected by the abundance of each isotope, leading to a slight fluctuation in the overall atomic mass of the element. Choice A is incorrect because isotopes do influence the atomic mass. Choice C is incorrect because isotopes have different masses, affecting the overall atomic mass. Choice D is incorrect as isotopes typically do not cause a significant variation in atomic mass, but rather a slight fluctuation.

2. Which of the following factors does not strengthen a scientific argument?

A. Lack of bias
B. Extensive use of qualitative research and data
C. Able to be reproduced and repeated by others
D. Withstands the test of time

Correct answer: B

Rationale: The correct answer is B. While qualitative data can provide valuable insights, it does not inherently strengthen a scientific argument to the same extent as quantitative data. Quantitative data is generally more precise, measurable, and easier to verify, making it a stronger basis for scientific arguments. Choices A, C, and D all contribute to strengthening a scientific argument. Lack of bias ensures objectivity and reliability, reproducibility by others validates the findings, and standing the test of time indicates the enduring validity and reliability of the argument.

3. Differentiate between epithelial and connective tissue.

A. Epithelial tissue lines surfaces and glands, while connective tissue supports tendons.
B. Both are composed of cells, but epithelial tissue lines surfaces and glands, while connective tissue binds other tissues.
C. Epithelial tissue covers surfaces and connective tissue supports muscle contraction.
D. Epithelial tissue is the largest tissue type, while connective tissue is the smallest.

Correct answer: B

Rationale: Epithelial tissue covers surfaces and lines organs, while connective tissue provides support and structure throughout the body. Both are composed of cells, but their functions and locations differ. Epithelial tissue acts as a barrier to protect underlying tissues and organs, while connective tissue connects, supports, and separates different types of tissues and organs in the body. Choice A is incorrect as connective tissue supports and binds other tissues, not just tendons. Choice C is incorrect because connective tissue does not support muscle contraction; it provides support to various structures in the body. Choice D is incorrect as the size of a tissue type does not define its function; epithelial tissue and connective tissue serve different purposes in the body.

4. What is the name for the sac-shaped structures in which carbon dioxide and oxygen exchange takes place?

A. Kidneys
B. Medulla oblongata
C. Alveoli
D. Bronchioles

Correct answer: C

Rationale: The alveoli are the tiny sac-shaped structures in the lungs where gas exchange occurs. Oxygen from the air we breathe diffuses into the bloodstream through the alveoli, while carbon dioxide, a waste product produced by cells, is removed from the blood and exhaled out of the body through the alveoli. Choices A, B, and D are incorrect. Kidneys are organs responsible for filtering waste from the blood, the medulla oblongata is a part of the brain responsible for autonomic functions, and bronchioles are smaller airway passages in the lungs that branch off from the bronchi.

5. Which of the following organs is responsible for churning and mechanically breaking down food?

A. Small intestine
B. Large intestine
C. Stomach
D. Esophagus

Correct answer: C

Rationale: The correct answer is C, the stomach. The stomach is responsible for churning and mechanically breaking down food. It contains muscles that contract and relax to mix food with digestive juices, breaking it down into smaller particles. This mechanical digestion process helps prepare the food for further digestion and absorption in the small intestine. The small intestine is primarily responsible for the absorption of nutrients, not for mechanical digestion. The large intestine absorbs water and salts, and the esophagus is a muscular tube that transports food from the mouth to the stomach, not involved in churning or breaking down food.