HESI A2
HESI A2 Version 1 Chemistry Questions
Question 1 of 5
What characterizes bases or alkaline solutions?
Correct Answer: A
Rationale: Bases or alkaline solutions are characterized by their ability to accept protons (hydrogen ions), making them hydrogen acceptors. When a base reacts with an acid, it accepts protons from the acid, forming water and a salt. This property distinguishes bases from acids, which donate protons. Therefore, the correct choice is A, as bases do not donate protons but instead accept them. This property allows bases to neutralize acids and regulate pH levels in solutions, making them crucial in maintaining the balance of acidity and alkalinity in various chemical systems.
Question 2 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 3 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 4 of 5
What is the term for the reactant that is fully consumed by the reaction?
Correct Answer: A
Rationale: The correct answer is 'limiting reactant.' In a chemical reaction, the limiting reactant is the substance that is entirely consumed when the reaction proceeds. It determines the extent of the reaction and limits the amount of product that can be formed. The other choices, such as 'reducing agent,' 'reaction intermediate,' and 'reagent,' do not specifically refer to the reactant that is fully consumed in the reaction.
Question 5 of 5
How can water be boiled at room temperature?
Correct Answer: B
Rationale: Water boils when its vapor pressure equals the atmospheric pressure. By increasing the pressure, the atmospheric pressure is reached at a lower temperature, allowing water to boil at room temperature. This phenomenon is utilized in specific scenarios such as high-altitude cooking where the reduced atmospheric pressure requires an increase in the boiling point to cook food properly. Therefore, the correct answer is by increasing the pressure.