HESI A2
HESI A2 Chemistry Questions
Question 1 of 5
Among the following elements, which is a nonmetal?
Correct Answer: C
Rationale: Step-by-step rationale: 1. Nonmetals are elements that lack metallic properties. 2. Sulfur is a nonmetal as it exists in a gaseous form at room temperature, lacks luster, and is a poor conductor of heat and electricity. 3. Mercury (A) is a metal as it is a liquid at room temperature. 4. Magnesium (B) and Potassium (D) are both metals as they are solid at room temperature and exhibit typical metallic properties. Summary: - A: Mercury is a metal. - B: Magnesium is a metal. - C: Sulfur is the correct answer as a nonmetal. - D: Potassium is a metal.
Question 2 of 5
If fifty-six kilograms of a radioactive substance has a half-life of 12 days, how many days will it take the substance to decay naturally to only 7 kilograms?
Correct Answer: C
Rationale: To determine the time for the substance to decay to 7 kg, we need to calculate the number of half-lives required. Each half-life reduces the substance by half. Given: Initial mass = 56 kg, Final mass = 7 kg, Half-life = 12 days. Number of half-lives = log(final mass / initial mass) / log(0.5) = log(7/56) / log(0.5) = 3.807 / -0.301 = -12.66. As the number of half-lives must be a whole number, we round up to 13 half-lives. Total time = 13 * 12 days = 156 days. Therefore, the correct answer is C (36 days). The other choices are incorrect because they do not accurately represent the calculation based on the half-life of the substance.
Question 3 of 5
Here are the solubilities of four substances at 0�C, in grams of solute per 100 mL of water. If the temperature increases to 20�C, what would you expect to happen to the solubility figures?
Correct Answer: C
Rationale: Failed to generate a rationale after 5 retries.
Question 4 of 5
What is the molarity of a solution containing 45 moles of NaCl in 4 liters?
Correct Answer: A
Rationale: To find molarity, divide moles of solute by liters of solution. In this case, molarity = 45 moles NaCl / 4 L = 11.25 M. However, NaCl is a salt, so you need to consider its formula weight (58.44 g/mol). Thus, 45 moles NaCl is 45 moles x 58.44 g/mol = 2634.6 g. Convert grams to kilograms (2634.6 g / 1000 = 2.6346 kg). Finally, molarity = 2.6346 kg / 4 L = 0.11 M NaCl. Choice A is correct because it accurately calculates the molarity. Choices B, C, and D are incorrect due to incorrect calculations.
Question 5 of 5
What is the correct name of ZnSO₄?
Correct Answer: A
Rationale: The correct answer is A: Zinc sulfate. ZnSO₄ consists of zinc (Zn) and sulfate (SO₄) ions. The name of an ionic compound follows the pattern of cation name + anion name with appropriate suffixes. In this case, "sulfate" is the correct name for the polyatomic ion SO₄, so the compound is named zinc sulfate. Incorrect choices: B: Zinc sulfide - Sulfide is a different anion (S²⁻) than sulfate. C: Zinc sulfur - Incorrect as it doesn't specify the anion involved. D: Zinc oxide - Oxide is a different anion (O²⁻) than sulfate.
Similar Questions
Join Our Community Today!
Join Over 10,000+ nursing students using Nurselytic. Access Comprehensive study Guides curriculum for HESI A2-HESI A2 and 3000+ practice questions to help you pass your HESI A2-HESI A2 exam.
Subscribe for Unlimited Access