what is 0k equal to in c

HESI A2

HESI A2 Chemistry

1. What is 0 K equal to in °C?

A. -300°C
B. -273°C
C. -250°C
D. -200°C

Correct answer: B

Rationale: 0 Kelvin, also known as absolute zero, is equal to -273°C. This is the point at which all molecular motion stops, making it the lowest possible temperature on the Kelvin scale. Choice A (-300°C) is incorrect as it is not the correct conversion of 0 K to °C. Choice C (-250°C) and Choice D (-200°C) are also incorrect as they do not correspond to the accurate conversion of 0 K to °C.

2. Which type of chemical bond is the strongest?

A. Ionic
B. Hydrogen
C. Covalent
D. Metallic

Correct answer: C

Rationale: Covalent bonds, especially those formed between non-metals, are the strongest type of chemical bond. In covalent bonds, atoms share electrons, creating a strong bond that requires a significant amount of energy to break. Choice A, ionic bonds, are strong but generally weaker than covalent bonds as they involve the transfer of electrons rather than sharing. Choice B, hydrogen bonds, are relatively weak intermolecular forces, not true chemical bonds. Choice D, metallic bonds, are strong but typically not as strong as covalent bonds. Metallic bonds involve a 'sea of electrons' shared between metal atoms, providing strength but with less directional bonding compared to covalent bonds.

3. Beta radiation is the product of the decomposition of which particle?

A. Proton
B. Neutron
C. Electron
D. Photon

Correct answer: B

Rationale: Beta radiation is the result of the decomposition of a neutron. During beta decay, a neutron in an atom's nucleus is transformed into a proton, an electron (beta particle), and an antineutrino. Therefore, the correct answer is 'Neutron.' Choice A, 'Proton,' is incorrect because beta decay does not involve the decomposition of a proton. Choice C, 'Electron,' is incorrect because electrons are actually produced during beta decay. Choice D, 'Photon,' is incorrect as beta radiation does not involve the decomposition of photons.

4. What does the mass number minus the atomic number equal?

A. Number of electrons
B. Number of neutrons
C. Number of protons
D. Number of isotopes

Correct answer: B

Rationale: The mass number of an atom represents the total number of protons and neutrons in its nucleus. The atomic number indicates the number of protons in the nucleus. The difference between the mass number and the atomic number provides the number of neutrons present in the nucleus of an atom. Therefore, mass number minus atomic number equals the number of neutrons. Choice A is incorrect because the number of electrons is not determined by the mass number and atomic number. Choice C is incorrect as it represents the number of protons, not the difference between the mass number and atomic number. Choice D is incorrect as isotopes refer to atoms of the same element with different numbers of neutrons, not the difference between mass number and atomic number.

5. 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.