what charge do alpha radiation particles have

HESI A2

Chemistry HESI A2 Quizlet

1. What charge do alpha radiation particles have?

A. -2
B. 0
C. +2
D. +1

Correct answer: C

Rationale: The correct answer is C: +2. Alpha radiation particles consist of two protons and two neutrons, giving them a net charge of +2. This positive charge is due to the presence of the two protons in the nucleus of the alpha particle. Choice A (-2) is incorrect as alpha particles have a positive charge. Choice B (0) is incorrect as alpha particles carry a charge. Choice D (+1) is incorrect as alpha particles have a higher positive charge due to the presence of two protons.

2. Which chemical reaction involves the formation of a single product from two or more reactants?

A. Synthesis reaction
B. Combustion reaction
C. Decomposition reaction
D. Double displacement reaction

Correct answer: A

Rationale: A synthesis reaction involves the combination of two or more reactants to form a single product. This type of reaction is characterized by the merging of substances to create a more complex compound. In a synthesis reaction, the reactants bond together to form a new product, making it the correct choice for this scenario. Combustion reactions involve the rapid combination of oxygen with another substance, resulting in the release of energy in the form of heat and light. Decomposition reactions entail the breakdown of a compound into simpler substances, often through the application of heat or electricity. Double displacement reactions involve the exchange of ions between two compounds, leading to the formation of two new compounds.

3. What is the oxidation state of the sulfur atom in sulfuric acid H2SO4?

A. 4
B. 6
C. 8
D. 10

Correct answer: B

Rationale: In sulfuric acid (H2SO4), sulfur has an oxidation state of +6. The oxidation state is determined by considering the overall charge of the compound and the known oxidation states of other elements. In this case, hydrogen is typically +1, and oxygen is -2. To balance the charges and match the compound's overall charge of 0, sulfur must have an oxidation state of +6. Choice A (4) is incorrect because it doesn't balance the charges in the compound. Choices C (8) and D (10) are also incorrect as they are not valid oxidation states for sulfur in this compound.

4. What is atomic mass?

A. Number of protons in an atom
B. Sum of protons and neutrons
C. Number of neutrons in an atom
D. Average weight of an element

Correct answer: B

Rationale: Atomic mass, also known as atomic weight, is the sum of the number of protons and neutrons in an atom. It represents the average mass of an atom of an element, taking into account the different isotopes and their relative abundance. Neutrons contribute to the atomic mass alongside protons, while the number of neutrons alone is not the definition of atomic mass. Choice A is incorrect because it refers only to the number of protons, not the complete atomic mass. Choice C is incorrect as it focuses solely on the number of neutrons, excluding the contribution of protons. Choice D is incorrect as it mentions the 'average weight of an element,' which is related to atomic mass but does not encapsulate the specific definition of atomic mass as the sum of protons and neutrons.

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?

A. 8
B. 12
C. 36
D. 48

Correct answer: C

Rationale: To decay from 56 kg to 7 kg, the substance needs to go through 3 half-lives (56 kg Ã· 2 Ã· 2 Ã· 2 = 7 kg). Since each half-life is 12 days, the total time required is 12 days per half-life x 3 half-lives = 36 days. Choice A is incorrect because it does not consider the concept of half-lives. Choice B is incorrect because it represents the duration of a single half-life, not the total time required for the decay. Choice D is incorrect as it does not account for the multiple half-lives needed for the substance to decay from 56 kg to 7 kg.