CMLA Chemistry Basics 2 — Questions and Answers
Question 1: Which type of chemical bond involves the complete transfer of electrons from one atom to another?
- Covalent bond
- Ionic bond (Correct answer)
- Hydrogen bond
- Van der Waals bond
Correct answer: Ionic bond
Ionic bonds form when one atom completely transfers electrons to another, creating oppositely charged ions that attract each other.
Question 2: A solution with a pH of 3 is how many times more acidic than a solution with a pH of 5?
- 2 times
- 10 times
- 100 times (Correct answer)
- 1000 times
Correct answer: 100 times
Each pH unit represents a 10-fold difference, so a difference of 2 pH units equals 100-fold difference in hydrogen ion concentration.
Question 3: Which of the following best describes an oxidation reaction?
- Gain of electrons
- Loss of electrons (Correct answer)
- Gain of protons
- Loss of protons
Correct answer: Loss of electrons
Oxidation is defined as the loss of electrons from a substance, while reduction is the gain of electrons.
Question 4: What is the molarity of a solution containing 2 moles of NaCl dissolved in 500 mL of water?
- 1 M
- 2 M
- 4 M (Correct answer)
- 0.5 M
Correct answer: 4 M
Molarity = moles of solute / liters of solution = 2 mol / 0.5 L = 4 M.
Question 5: In a clinical lab, a buffer solution is used primarily to:
- Increase the reaction temperature
- Resist changes in pH (Correct answer)
- Speed up enzymatic reactions
- Dissolve precipitates
Correct answer: Resist changes in pH
Buffers resist changes in pH by neutralizing added acids or bases, maintaining a stable environment for chemical reactions.
Question 6: Which of the following is a property of water that makes it an excellent biological solvent?
- It is nonpolar
- It has high polarity and hydrogen bonding (Correct answer)
- It has low surface tension
- It is a weak electrolyte
Correct answer: It has high polarity and hydrogen bonding
Water's polar nature and hydrogen bonding ability allow it to dissolve a wide range of ionic and polar substances found in biological systems.
Question 7: A laboratory technician prepares a 1:10 dilution of a patient serum sample. If the original concentration of glucose is 200 mg/dL, what is the concentration in the diluted sample?
- 2000 mg/dL
- 200 mg/dL
- 20 mg/dL (Correct answer)
- 2 mg/dL
Correct answer: 20 mg/dL
A 1:10 dilution means 1 part sample in 10 parts total, so the concentration is divided by 10: 200 / 10 = 20 mg/dL.
CMLA Chemistry Basics 2
Which type of chemical bond involves the complete transfer of electrons from one atom to another?