HESI A2
HESI A2 Version 1 Chemistry Questions
Question 1 of 5
What is the name for the horizontal rows of the periodic table?
Correct Answer: B
Rationale: In the periodic table, the horizontal rows are called 'periods.' These periods represent the number of electron shells an element has. Each period starts a new energy level, indicating the elements' properties and atomic structure. 'Groups' refer to the vertical columns of the periodic table, each containing elements with similar chemical properties. 'Families' can also be used interchangeably with groups. 'Sets' is a vague term and not specifically related to the layout of the periodic table. Understanding the distinction between 'periods' and 'groups' is crucial in comprehending the organization and properties of elements in the periodic table.
Question 2 of 5
What is the pH of a solution with a pH of 7?
Correct Answer: C
Rationale: The correct answer is C: Neutral. A pH of 7 is considered neutral on the pH scale, which ranges from 0 to 14. A pH of 7 indicates a balance between acidic and basic properties in a solution, making it neither acidic nor basic. Values below 7 are acidic, above 7 are basic, and 7 is the midpoint representing neutrality. Therefore, a solution with a pH of 7 is neutral.
Question 3 of 5
What is the name of the device that separates gaseous ions by their mass-to-charge ratio?
Correct Answer: A
Rationale: The correct answer is a mass spectrometer. A mass spectrometer is a device specifically designed to separate gaseous ions based on their mass-to-charge ratio. The separation occurs as ions pass through the mass spectrometer, allowing for the identification and quantification of compounds present in a sample. This analytical instrument is widely used in chemistry and other scientific fields due to its ability to provide detailed information about the composition of substances.
Question 4 of 5
What does the term 'atomic number' represent?
Correct Answer: B
Rationale: The atomic number represents the number of protons in the nucleus of an atom. This number uniquely identifies an element and determines its placement in the periodic table. The number of neutrons and electrons can vary among different isotopes of an element, but the number of protons remains constant, defining the element's atomic number. Therefore, the correct answer is the number of protons (Choice B).
Question 5 of 5
What is a benefit of water's ability to make hydrogen bonds?
Correct Answer: D
Rationale: The correct answer is D - High specific heat. Water's ability to make hydrogen bonds leads to a high specific heat capacity, which allows it to absorb and release large amounts of heat with minimal temperature change. This property is crucial for maintaining stable temperatures in living organisms and aquatic environments. High specific heat helps regulate body temperature in organisms and prevents sudden temperature fluctuations in water bodies, providing an essential benefit for various biological processes.