Nursing Elites

1. 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.

2. What is the coefficient of O after the following equation is balanced?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: A

Rationale: In a balanced chemical equation, the coefficient of oxygen (O) in O2 is already 2, so there is no need to adjust its coefficient further. Therefore, the coefficient of O remains as 1. Since the coefficient of O2 is 2, each O atom is represented by the coefficient of 1, and it does not change during the balancing process. Choices B, C, and D are incorrect as they suggest changing the coefficient of oxygen, which is not necessary for O2 in a balanced equation.

3. Which elements are typically involved in hydrogen bonding?

• A. Carbon, hydrogen, oxygen
• B. Fluorine, chlorine, oxygen
• C. Fluorine, chlorine, nitrogen
• D. Fluorine, oxygen, nitrogen

Correct answer: D

Rationale: Hydrogen bonding occurs between hydrogen and highly electronegative atoms such as fluorine, oxygen, and nitrogen. These atoms have a strong pull on the shared electrons, leading to a partial negative charge on them, which allows them to form hydrogen bonds with hydrogen or other electronegative atoms. Choice A is incorrect because carbon is not typically involved in hydrogen bonding. Choice B is incorrect because chlorine is not as electronegative as nitrogen, and choice C is incorrect because nitrogen is more electronegative than chlorine.

4. How many electron pairs are shared to form a double covalent bond?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: B

Rationale: The correct answer is B. In a double covalent bond, two pairs of electrons are shared between two atoms. This sharing of two electron pairs results in a stronger bond compared to a single covalent bond where only one pair of electrons is shared. Choice A is incorrect because a single covalent bond involves the sharing of one pair of electrons. Choices C and D are incorrect as they do not represent the correct number of electron pairs shared in a double covalent bond.

5. Which gas is produced when an acid reacts with a carbonate?

• A. Carbon dioxide
• B. Oxygen
• C. Hydrogen
• D. Nitrogen

Correct answer: A

Rationale: When an acid reacts with a carbonate, the chemical reaction typically yields carbon dioxide gas. Carbon dioxide is formed due to the chemical reaction between the acid and the carbonate, releasing this gas as a product. Therefore, the correct answer is 'Carbon dioxide.' Choices B, C, and D are incorrect as oxygen, hydrogen, and nitrogen are not the gases produced in this specific acid-carbonate reaction.

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