HESI A2
HESI A2 Version 1 Chemistry Questions
Question 1 of 5
What is a combustion reaction?
Correct Answer: D
Rationale: A combustion reaction is a type of chemical reaction that involves a substance reacting with oxygen gas to produce heat and light. This reaction is exothermic, releasing energy in the form of heat and light. The correct answer is D because combustion reactions specifically involve oxygen as a reactant, leading to the production of heat and light as byproducts.
Question 2 of 5
What is the name for a reaction in which electrons are transferred from one atom to another?
Correct Answer: C
Rationale: A redox reaction, also known as a reduction-oxidation reaction, involves the transfer of electrons from one substance to another. During this process, one substance is oxidized (loses electrons) while another is reduced (gains electrons). This transfer of electrons is a key characteristic of redox reactions, making choice C the correct answer. Combustion reaction (choice A) involves a substance reacting with oxygen to produce heat and light, but it does not necessarily involve electron transfer. Synthesis reaction (choice B) involves the combination of two or more substances to form a new compound, without necessarily involving electron transfer. Double-displacement reaction (choice D) involves the exchange of ions between two compounds, but not the transfer of electrons from one atom to another.
Question 3 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.
Question 4 of 5
What is the correct name for aqueous HI?
Correct Answer: A
Rationale: The correct name for aqueous HI is hydroiodic acid. In the naming of binary acids, the prefix 'hydro-' is combined with the root of the nonmetal element and the suffix '-ic acid'. Therefore, the correct systematic name for HI in aqueous solution is hydroiodic acid.
Question 5 of 5
What is the term for the number of protons in an atom?
Correct Answer: D
Rationale: The term for the number of protons in an atom is the atomic number. The atomic number is a fundamental property of an element, representing the number of protons in an atom's nucleus. It serves as the unique identity of an element and determines its position on the periodic table and its chemical behavior. Atomic mass refers to the average mass of an atom, including protons, neutrons, and electrons, while atomic weight is the average weight of an element considering the abundance of its isotopes. 'Atomic identity' is not a standard term in chemistry to describe the number of protons in an atom, making option D, 'atomic number,' the correct answer.