chemical reaction that consists of an active metal reacting with an ionic compound to create a new compound

HESI A2

Chemistry HESI A2 Quizlet

1. 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.

2. Radioactive isotopes are frequently used in medicine. What kind of half-life would a medical isotope probably have?

A. Seconds-long
B. Days-long
C. Years-long
D. Many years long

Correct answer: B

Rationale: Medical isotopes used in diagnosis and treatment need to have a relatively short half-life to minimize radiation exposure to patients. If the half-life were too long (such as many years) or even years-long, the radiation would persist for too long and could be harmful to the patient. Seconds-long half-lives would not provide enough time for the isotope to be effective. Days-long half-lives strike a balance between providing enough time for the isotope to be used effectively and minimizing radiation exposure.

3. Which element is considered a noble gas?

A. Oxygen
B. Neon
C. Hydrogen
D. Argon

Correct answer: B

Rationale: The correct answer is 'Neon.' Noble gases are a group of elements with very low reactivity. Neon is one of these elements, known for its stable and unreactive nature. Oxygen, hydrogen, and argon do not belong to the noble gas group. Oxygen is a reactive non-metal, hydrogen is a non-metal and the first element in the periodic table, and argon is a noble gas like neon but not the correct answer in this case.

4. Balance this equation: Zn + HCl â†’ ZnCl + H2.

A. Zn + 2HCl â†’ ZnCl + H2
B. Zn + HCl â†’ 2ZnCl + H2
C. 2Zn + 2HCl â†’ 2ZnCl + H2
D. Zn + 4HCl â†’ ZnCl + H2

Correct answer: C

Rationale: The given unbalanced equation is Zn + HCl â†’ ZnCl + H2. To balance it, we need to have equal atoms on both sides of the equation. The balanced equation is 2Zn + 2HCl â†’ 2ZnCl + H2. This balanced equation shows that two atoms of Zn combine with two molecules of HCl to form two molecules of ZnCl and one molecule of H2. Choice A is incorrect because it does not balance the equation. Choice B is incorrect as it does not have the same number of atoms on both sides. Choice D is incorrect because it does not balance the equation properly, resulting in an unequal number of atoms on both sides.

5. What type of chemical reaction involves the combination of two elements to form a product?

A. Decomposition
B. Combustion
C. Synthesis
D. Double replacement

Correct answer: C

Rationale: A synthesis reaction involves the combination of two or more substances to form a single, more complex product. In the context of chemical reactions, it specifically refers to the combination of two elements to form a compound. Therefore, the correct answer is C. Decomposition reactions involve the breakdown of a single compound into simpler substances (opposite of synthesis). Combustion reactions involve a substance reacting with oxygen to produce heat and light, not the combination of elements. Double replacement reactions involve the exchange of ions between two compounds, leading to the formation of two new compounds, not the combination of two elements.