Question 1: Define a carbonate ion and give its chemical formula.

Answer: A carbonate ion is a polyatomic ion with the formula CO₃²⁻, consisting of one carbon atom bonded to three oxygen atoms with a 2- charge.

Question 2: Describe the typical reaction that occurs when a carbonate reacts with an acid.

Answer: The carbonate reacts with acid to produce carbon dioxide gas, water, and a salt, often evidenced by bubbling or effervescence.

Question 3: Explain why carbonates are classified as basic salts.

Answer: Because they are derived from a weak acid (carbonic acid) and a strong base (like sodium hydroxide), making them basic in nature.

Question 1: Calculate the mass of calcium carbonate (CaCO₃) required to prepare 250 cm³ of a 0.1 mol/dm³ solution.

Answer: Mass = moles × molar mass = 0.025 mol × 100.09 g/mol = 2.502 g

Question 2: If 50 cm³ of an acid reacts completely with 0.2 g of sodium carbonate, what is the concentration of the acid? (Molar mass of Na₂CO₃ = 105.99 g/mol).

Answer: Number of moles Na₂CO₃ = 0.2 g / 105.99 g/mol = 0.00189 mol Volume in dm³ = 0.05 dm Concentration = 0.00189 mol / 0.05 dm³ = 0.0378 mol/dm³

Question 1: Describe a safe method to test for the presence of carbonate ions in a mineral sample.

Answer: Add dilute acid to the sample and observe for bubbles of carbon dioxide gas, indicating the presence of carbonate ions.

Question 2: Identify two variables that must be controlled during the reaction of a carbonate with acid in an experiment.

Answer: Concentration of acid and temperature.

Question 3: State a safety precaution to take when handling acids in carbonate testing experiments.

Answer: Wear safety goggles and gloves to protect against splashes of corrosive acids.

Question 1: A student adds dilute hydrochloric acid to a mineral sample and observes vigorous bubbling. Explain the chemical process occurring and how it confirms the presence of carbonate ions.

Answer: The acid reacts with carbonate ions in the mineral to produce carbon dioxide gas, water, and a salt. The vigorous bubbling indicates the release of CO₂, confirming the presence of carbonate ions.

Question 1: Describe the steps to test if a rock contains carbonate minerals and explain the scientific principle behind the test.

Answer: Place a small piece of the rock in a test tube, add dilute hydrochloric acid, and observe for bubbling of carbon dioxide gas. The reaction occurs because acids react with carbonate minerals to produce CO₂, which causes effervescence. This confirms the presence of carbonate ions in the mineral.

Question 1: Explain how the detection of carbonate ions is important in the quality control of water supplies.

Answer: Detecting carbonate ions helps identify hardness in water, which can cause scaling in pipes and appliances. Monitoring carbonate levels ensures water quality and prevents damage.

Question 2: Describe a practical industrial use of carbonate compounds.

Answer: Carbonate compounds like sodium carbonate are used in glass manufacturing, pH regulation, and as cleaning agents.