Question 1: Define oxidation and reduction in terms of electron transfer.

Answer: Oxidation is the loss of electrons, and reduction is the gain of electrons.

Question 2: Explain why oxidation and reduction always occur together in chemical reactions.

Answer: Because electrons lost in oxidation are gained in reduction, so both processes happen simultaneously.

Question 1: Calculate the oxidation state of sulfur in sulfuric acid (H2SO4).

Answer: +6

Question 2: In a reaction, 2 grams of aluminum (Al) reacts with oxygen to form aluminum oxide. Calculate the number of moles of aluminum used, given that the molar mass of Al is 26.98 g/mol.

Answer: 0.0741 mol

Question 1: Describe a safe method to test whether a metal sample is reactive with acid.

Answer: Add a small piece of the metal to dilute acid in a test tube and observe for fizzing or gas production, while wearing safety goggles and gloves.

Question 2: Identify the independent and dependent variables in an experiment measuring the reactivity of different metals with hydrochloric acid.

Answer: Independent variable: type of metal; Dependent variable: amount of hydrogen gas produced.

Question 1: A metal reacts slowly with water, forming a hydroxide and releasing hydrogen gas. What does this suggest about its reactivity, and which metal might it be?

Answer: It suggests low reactivity; likely a less reactive metal such as zinc or iron.

Question 2: In a reaction, a metal's oxidation number increases from 0 to +2. What does this indicate about the metal's role?

Answer: The metal is undergoing oxidation, acting as a reducing agent.

Question 1: Describe the process of oxidation and reduction in the context of a metal reacting with oxygen. Include the electron transfer involved.

Answer: When a metal reacts with oxygen, it loses electrons and undergoes oxidation, forming a metal oxide. The metal atoms transfer electrons to oxygen molecules, which gain them and become oxide ions. This simultaneous process is essential for forming metal oxides and demonstrates the fundamental concept of oxidation and reduction.

Question 1: Describe how galvanization uses oxidation and reduction principles to prevent rusting of steel.

Answer: Galvanization involves coating steel with zinc. Zinc undergoes oxidation, protecting the steel from rusting by sacrificing itself, thus preventing iron oxidation.

Question 2: Explain how the reactivity series helps in selecting metals for batteries and electrochemical cells.

Answer: The reactivity series ranks metals by their tendency to lose electrons. More reactive metals are used as anodes, and less reactive metals as cathodes, optimizing electron flow and efficiency in batteries.