ATI TEAS 7
Chemistry
1. What is the formula for calculating molarity?
- A. M = n/V
- B. M = n/L
- C. M = mol/L
- D. M = mol/dm³
Correct answer: a
Rationale: All of these choices are equivalent to the original formula. The symbol "n" represents the number of moles of solute, and the symbol "V" represents the volume of the solution in liters. The symbol "L" is an abbreviation for "liters," and "dm³" is an alternative way to represent liters.
2. The endocrine system communicates through chemical messengers called:
- A. Enzymes
- B. Hormones
- C. Antibodies
- D. Neurons
Correct answer: B
Rationale: The correct answer is B: Hormones. The endocrine system communicates through hormones, which are chemical messengers produced by various glands in the body. These hormones are released into the bloodstream and travel to target organs or tissues to regulate a wide range of bodily functions. Enzymes (A) are biological molecules that catalyze chemical reactions, not chemical messengers for communication within the body. Antibodies (C) are involved in the immune system's response to foreign substances. Neurons (D) are part of the nervous system and communicate through electrical impulses rather than chemical messengers like hormones.
3. Which term describes the functional unit of a skeletal muscle responsible for muscle contraction?
- A. Myofibril
- B. Sarcomere
- C. Tendon
- D. Myoglobin
Correct answer: b
Rationale: The correct answer is B: Sarcomere. A sarcomere is the functional unit of a skeletal muscle responsible for muscle contraction. It is made up of overlapping filaments of actin and myosin proteins. Myofibrils are long, cylindrical structures within muscle cells that contain sarcomeres. Tendons are tough bands of fibrous connective tissue that connect muscles to bones and facilitate movement. Myoglobin is a protein found in muscle cells that stores oxygen for muscle use during exercise. Therefore, the sarcomere is specifically responsible for muscle contraction, making it the correct answer in this question.
4. Which sentence uses the gerund (-ing) form correctly?
- A. My favorite activity is playing tennis.
- B. He enjoys to travel to new places.
- C. Reading a good book is relaxing.
- D. Writing is her passion.
Correct answer: A
Rationale: Option A uses the gerund as the direct object of "is," while the other options lack a clear function for the -ing form.
5. A lampshade consists of a cylindrical base (diameter 20cm, height 10cm) and a hemispherical top (same diameter as the base). What is its total surface area?
- A. 785 sq cm
- B. 1130 sq cm
- C. 1570 sq cm
- D. 2055 sq cm
Correct answer: D
Rationale: Calculate the surface area of the cylinder (base + lateral surface) and the hemisphere (half of a sphere's surface area). Add both areas to find the total surface area.
6. The stomach produces a strong acid to help break down food. What is the name of this acid?
- A. Hydrochloric acid
- B. Lactic acid
- C. Bile
- D. Fatty acid
Correct answer: A
Rationale: The correct answer is A: Hydrochloric acid. The stomach produces hydrochloric acid to help break down food by lowering the pH level in the stomach, creating an acidic environment that aids in the digestion of proteins and other nutrients. Lactic acid is produced in muscles during exercise and is not related to stomach digestion. Bile is produced by the liver and helps in the digestion and absorption of fats in the small intestine. Fatty acids are a type of molecule that is a component of fats, not the acid produced by the stomach for digestion.
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