Question 1: Define the term 'mole' in chemistry.

Answer: A mole is the amount of substance that contains exactly 6.022 x 10²³ particles (atoms, molecules, or ions).

Question 2: Explain why the mole is a useful unit in chemistry.

Answer: The mole allows chemists to count particles by weighing substances, making calculations easier when dealing with very large numbers of particles.

Question 1: Calculate the number of moles in 12 grams of carbon dioxide (CO₂). (Molar mass of CO₂ = 44 g/mol)

Answer: Moles = 12 g / 44 g/mol = 0.273 moles

Question 2: A sample of aluminium weighs 27 grams. Calculate the number of moles of aluminium. (Molar mass of Al = 27 g/mol)

Answer: Moles = 27 g / 27 g/mol = 1 mole

Question 1: Describe the key safety precautions one should take when weighing chemicals to determine moles in a laboratory setting.

Answer: Wear safety goggles, handle chemicals with care to avoid spills, use appropriate gloves, and ensure the balance is calibrated properly.

Question 2: Identify two variables that must be controlled during a mass measurement for mole calculation.

Answer: Temperature and humidity, to prevent inaccuracies in weighing.

Question 1: A researcher measures 5 grams of sulphur. Given sulphur's molar mass is 32 g/mol, how many moles are present? What does this tell you about the number of particles?

Answer: Moles = 5 g / 32 g/mol = 0.156 moles; this corresponds to approximately 9.39 x 10²² particles.

Question 1: Explain how understanding the concept of moles can aid in industrial chemical manufacturing, including an example of a process where mole calculations are essential.

Answer: Understanding moles allows industrial chemists to accurately measure reactants and products, ensuring correct proportions for efficiency and safety. For example, in ammonia synthesis via the Haber process, mole ratios of nitrogen to hydrogen are critical to optimise yield and minimise waste.

Question 1: Discuss how mole calculations are used in the food industry, giving a specific example.

Answer: Mole calculations are used to determine the amount of ingredients in chemical preservatives or additives, ensuring correct dosages for safety and effectiveness, such as calculating the amount of sulphur dioxide in wine preservation.