ATDH - Admission Test for Dental Hygiene General Chemistry Principles Questions and Answers

Question 1

The critical pH for enamel demineralization is approximately 5.5.
A patient consumes a beverage with a hydronium ion [H₃O⁺] concentration of 1.0 x 10⁻⁴ M.
What is the pH of this beverage, and what is its likely effect on tooth enamel?

Accepted Answer

pH = 4; Demineralizing

Answer

pH = 10; Remineralizing

Answer

pH = 4; Remineralizing

Answer

pH = 10; Demineralizing

Question 2

Sodium fluoride (NaF), a common ingredient in toothpaste, is formed when a sodium atom transfers a valence electron to a fluorine atom. What type of chemical bond is formed between the resulting sodium and fluoride particles?

Accepted Answer

Ionic bond

Answer

Covalent bond

Answer

Hydrogen bond

Answer

Metallic bond

Question 3

A dental hygienist needs to prepare 500 mL of a 0.2 M saline solution (NaCl) for a patient rinse. How many grams of sodium chloride (NaCl) are required? (Molar mass of NaCl ≈ 58.44 g/mol)

Accepted Answer

5.84 g

Answer

11.69 g

Answer

29.22 g

Answer

0.10 g

Question 4

Carbon-12 and Carbon-14 are two isotopes of carbon. Which of the following statements correctly describes the difference between an atom of Carbon-14 and an atom of Carbon-12?

Accepted Answer

Carbon-14 has two more neutrons than Carbon-12.

Answer

Carbon-14 has two more protons than Carbon-12.

Answer

Carbon-14 has two more electrons than Carbon-12.

Answer

Carbon-14 has two fewer protons than Carbon-12.

Question 5

Hydrogen peroxide (H₂O₂) is used as a whitening agent because it decomposes into water (H₂O) and oxygen gas (O₂). This is a type of redox reaction known as a disproportionation reaction. What does this mean for the oxygen atoms in H₂O₂?

Accepted Answer

The oxygen atoms are simultaneously oxidized and reduced.

Answer

The oxygen atoms only undergo oxidation.

Answer

The oxygen atoms only undergo reduction.

Answer

The oxygen atoms are transferred but their oxidation state is unchanged.

Question 6

A reversible hydrocolloid impression material is heated to become a liquid and then cooled in a tray to become a semisolid gel in the patient's mouth. The physical process of changing from a liquid state to a solid state is called:

Accepted Answer

Solidification (or Freezing)

Answer

Sublimation

Answer

Condensation

Answer

Evaporation

The critical pH for enamel demineralization is approximately 5.5.A patient consumes a beverage with a hydronium ion [H₃O⁺] concentration of 1.0 x 10⁻⁴ M.What is the pH of this beverage, and what is its likely effect on tooth enamel?

The critical pH for enamel demineralization is approximately 5.5.
A patient consumes a beverage with a hydronium ion [H₃O⁺] concentration of 1.0 x 10⁻⁴ M.
What is the pH of this beverage, and what is its likely effect on tooth enamel?