what is the boiling point of water in f

HESI A2

HESI A2 Chemistry Practice Test

1. At what temperature does water boil in Â°F?

A. 210Â°F
B. 212Â°F
C. 215Â°F
D. 220Â°F

Correct answer: B

Rationale: Water boils at 212Â°F under standard atmospheric pressure. This is the point at which water changes from a liquid to a gas phase. Choice A (210Â°F) is incorrect as it is below the boiling point of water. Choice C (215Â°F) and Choice D (220Â°F) are also incorrect as they are above the boiling point of water.

2. What is the oxidation state of the nitrogen atom in the compound NH3?

A. -3
B. -1
C. +1
D. +3

Correct answer: B

Rationale: In the compound NH3, nitrogen is bonded to three hydrogen atoms. Hydrogen is always assigned an oxidation state of +1. Since the overall charge of NH3 is zero, the oxidation state of nitrogen must be -1 to balance out the hydrogen's +1 oxidation state. Therefore, the correct oxidation state of the nitrogen atom in NH3 is -1. Choice A (-3) is incorrect because it does not account for the electronegativity of hydrogen. Choice C (+1) and Choice D (+3) are incorrect as the nitrogen atom in NH3 needs to balance the +1 oxidation state of each hydrogen atom, resulting in a total of -3 to maintain the compound's charge neutrality.

3. In the periodic table, which group contains the alkali metals?

A. Group 7
B. Group 1
C. Group 2
D. Group 3

Correct answer: B

Rationale: The correct answer is Group 1. Alkali metals are found in Group 1 of the periodic table, which includes elements such as lithium, sodium, and potassium. These elements are known for their high reactivity and tendency to form alkaline solutions when they react with water. Therefore, Group 1 is specifically designated as the group containing alkali metals. Choice A (Group 7) is incorrect as Group 7 contains the halogens. Choice C (Group 2) is incorrect as Group 2 contains the alkaline earth metals. Choice D (Group 3) is incorrect as Group 3 contains the scandium group of elements.

4. Which is a property of an ionic compound?

A. Low melting point
B. Poor conductivity
C. Shared electrons
D. Crystalline shape

Correct answer: D

Rationale: Ionic compounds are composed of positively and negatively charged ions that are held together by strong electrostatic forces. These ions arrange themselves in a repeating pattern to form a stable and orderly structure known as a crystalline shape. This is a characteristic property of ionic compounds, making choice D the correct answer. Choices A, B, and C are incorrect because ionic compounds typically have high melting points, good conductivity in the molten or dissolved state, and do not involve shared electrons but rather the transfer of electrons between atoms.

5. Which element has an atomic mass greater than that of sodium?

A. Boron
B. Oxygen
C. Fluorine
D. Silicon

Correct answer: D

Rationale: Silicon has an atomic mass greater than that of sodium. The atomic mass of silicon is approximately 28.0855 u, whereas the atomic mass of sodium is approximately 22.9898 u. Therefore, silicon has a greater atomic mass compared to sodium. Boron, Oxygen, and Fluorine have atomic masses lower than sodium, making them incorrect choices in this context.