TEAS 7 Chemistry: Essential Practice for Success

ATI TEAS 7

Chemistry

1. What is the pH of a solution with a hydrogen ion concentration of $1 \times 10^{-9}$ M?

A. 5
B. 7
C. 9
D. 11

Correct answer: c

Rationale: The pH is calculated as the negative logarithm (base 10) of the hydrogen ion concentration. In this case, $-\log(1 \times 10^{-9}) = 9$.

2. The electrical conductivity of a strong acid solution is higher than that of a weak acid solution because:

A. Strong acids are more concentrated.
B. Strong acids release more hydrogen ions
C. Weak acids are better at dissolving salts.
D. Strong acids have a lower pH.

Correct answer: B

Rationale: Strong acids completely dissociate, leading to a h

3. Which hormone stimulates the release of pancreatic enzymes and bile?

A. Gastrin
B. Insulin
C. Cholecystokinin (CCK)
D. Glucagon

Correct answer: C

Rationale: The correct answer is C: Cholecystokinin (CCK). Cholecystokinin is a hormone produced by the small intestine in response to the presence of food, especially fats and proteins. It stimulates the release of pancreatic enzymes from the pancreas and bile from the gallbladder to aid in digestion. Gastrin is a hormone that stimulates the release of gastric acid in the stomach. Insulin and glucagon are hormones involved in regulating blood sugar levels, not the release of pancreatic enzymes and bile. Therefore, CCK is the hormone responsible for stimulating the release of pancreatic enzymes and bile in the digestive process.

4. A new material is claimed to be stronger than steel. You design an experiment to test this claim. What is the MOST important control variable?

A. The size of the material samples.
B. The temperature at which the test is conducted.
C. The force applied to the material.
D. The color of the material.

Correct answer: A

Rationale: The size of the material samples is the most important control variable because it ensures that the comparison between the new material and steel is fair and accurate. By keeping the size consistent, any differences in strength can be attributed to the material composition rather than variations in sample size. Controlling for size helps eliminate confounding variables and increases the reliability of the experiment results. Temperature, force applied, and color are not as critical for directly testing the strength comparison between the new material and steel.

5. Polymers are

A. Large molecules formed by repeating units called monomers
B. Simple organic molecules with low boiling points
C. Highly reactive compounds used in industrial processes
D. Insoluble solids with no definite structure

Correct answer: A

Rationale: The correct answer is A: 'Large molecules formed by repeating units called monomers.' Polymers are macromolecules made up of repeating units called monomers, which are linked together through chemical bonds. This repetition results in long chains or networks of molecules, giving polymers their unique properties. Options B, C, and D are incorrect because polymers are not simple organic molecules with low boiling points, highly reactive compounds used in industrial processes, or insoluble solids with no definite structure. Understanding the basic definition of polymers helps us appreciate their wide range of applications in materials science, engineering, and everyday products.