HESI A2
HESI A2 Chemistry
1. Which of these elements has the greatest atomic mass?
- A. Au
- B. Ba
- C. I
- D. W
Correct answer: D
Rationale: Among the elements listed, Tungsten (W) has the greatest atomic mass. The atomic mass of Tungsten is approximately 183.84 atomic mass units (amu), while the atomic masses of the other elements listed are as follows: Gold (Au) is around 196.97 amu, Barium (Ba) is approximately 137.33 amu, and Iodine (I) is about 126.90 amu. Therefore, Tungsten (W) has the greatest atomic mass out of the given elements. Gold (Au) has a higher atomic mass than Barium (Ba) and Iodine (I), making choices A, B, and C incorrect.
2. What is the oxidation state of the chlorine atom in the compound HCl?
- A. +1
- B. -1
- C. +2
- D. -2
Correct answer: B
Rationale: In the compound HCl (hydrochloric acid), the hydrogen atom has an oxidation state of +1 based on the rules of assigning oxidation states. Since the overall compound is neutral, the oxidation state of chlorine must be -1 to balance the charge. Chlorine typically has an oxidation state of -1 in binary compounds with nonmetals, such as HCl. Therefore, the correct answer is -1. Choices A, C, and D are incorrect as the oxidation state of chlorine in HCl is -1, not +1, +2, or -2.
3. Which best defines the molarity of an aqueous sugar solution?
- A. Grams of sugar per milliliter of solution
- B. Moles of sugar per milliliter of solution
- C. Grams of sugar per liter of solution
- D. Moles of sugar per liter of solution
Correct answer: D
Rationale: The molarity of a solution is defined as the number of moles of solute per liter of solvent. In the case of an aqueous sugar solution, the molarity would be expressed as moles of sugar per liter of solution. This is because molarity is a measurement of the concentration of a solute in a solution based on the number of moles present in a given volume of the solution. Therefore, the correct answer is D. Choices A, B, and C are incorrect because the molarity is specifically defined in terms of moles of solute per liter of solution, not in grams per milliliter or grams per liter. Molarity is a unit of concentration that relates the amount of solute to the volume of the solution, not the mass of the solute.
4. What charge do Group VIA elements typically have?
- A. -1
- B. -2
- C. -3
- D. 0
Correct answer: B
Rationale: Group VIA elements, also known as Group 16 elements, typically have a charge of -2. This is because they have 6 valence electrons and tend to gain 2 electrons to achieve a stable octet configuration, resulting in a -2 charge. Choice A (-1) is incorrect as Group VIA elements need to gain 2 electrons for stability, not just 1. Choice C (-3) is incorrect because Group VIA elements do not need to gain 3 electrons to achieve stability. Choice D (0) is incorrect as Group VIA elements need to gain electrons to reach a stable configuration, resulting in a negative charge.
5. Which type of chemical reaction involves an active metal reacting with an ionic compound to create a new compound?
- A. Combustion
- B. Single replacement
- C. Synthesis
- D. Decomposition
Correct answer: B
Rationale: The correct answer is 'Single replacement.' In a single replacement reaction, an active metal replaces another element in an ionic compound, resulting in the formation of a new compound. Option A, 'Combustion,' involves a substance rapidly reacting with oxygen to release energy in the form of heat and light. Option C, 'Synthesis,' involves the combination of two or more substances to form a more complex product. Option D, 'Decomposition,' involves the breakdown of a compound into simpler substances.
Similar Questions
Access More Features
HESI A2 Basic
$99/ 30 days
- 3,000 Questions with answers
- 30 days access
HESI A2 Premium
$149.99/ 90 days
- Actual HESI A2 Questions
- 3,000 questions with answers
- 90 days access