Question 1: Define the Avogadro Constant and state its value in particles per mole.

Answer: The number of particles (atoms, molecules, or ions) in one mole of a substance, approximately 6.022 x 10^23 particles per mole.

Question 2: Explain why the Avogadro Constant is important in quantifying substances in environmental science.

Answer: It allows scientists to determine the number of particles in a given mass of a substance, which is crucial for understanding chemical reactions and pollutant quantities in the environment.

Question 3: What is the significance of Avogadro’s Law in relation to gases and environmental monitoring?

Answer: It states that equal volumes of gases at the same temperature and pressure contain an equal number of particles, aiding in measuring and modelling atmospheric gases.

Question 4: Calculate the number of sulphur atoms in 5 grams of sulphur, given that the molar mass of sulphur is 32.07 g/mol.

Answer: Number of atoms = (mass / molar mass) x Avogadro Constant = (5 / 32.07) mol x 6.022 x 10^23 particles/mol ≈ 9.39 x 10^22 atoms

Question 1: How many molecules are present in 2.5 grams of methane (CH₄)? Molar mass of CH₄ = 16.04 g/mol.

Answer: Number of moles = 2.5 / 16.04 ≈ 0.1558 mol Number of molecules = 0.1558 mol x 6.022 x 10^23 ≈ 9.39 x 10^22 molecules

Question 2: A sample contains 1.204 x 10^24 particles of nitrogen molecules (N₂). How many moles does this represent?

Answer: Moles = particles / Avogadro Constant = 1.204 x 10^24 / 6.022 x 10^23 ≈ 2 mol

Question 1: Describe a simple theoretical experiment to determine the molar mass of a gas using the principles of the Avogadro Constant.

Answer: The experiment involves measuring the volume, pressure, and temperature of a known mass of gas. Using the ideal gas law (PV=nRT), the number of moles (n) can be calculated, then combined with the mass to find molar mass. The number of particles can be inferred by multiplying moles by Avogadro's Constant.

Question 2: Identify two safety precautions that must be taken when handling gases in environmental sampling experiments.

Answer: Ensure proper ventilation to avoid inhalation of toxic gases; use appropriate personal protective equipment such as gloves and safety goggles.

Question 1: A pollutant in the atmosphere is measured to be at a concentration of 3.0 x 10^15 particles per cubic metre. How many moles of particles are present in a 10 m³ sample?

Answer: Total particles = 3.0 x 10^15 x 10 = 3.0 x 10^16 particles Moles = 3.0 x 10^16 / 6.022 x 10^23 ≈ 4.98 x 10^-8 mol

Question 2: Explain how understanding the number of particles in pollutants can influence environmental policies and pollution control strategies.

Answer: Knowing the number of pollutant particles helps quantify pollution levels accurately, enabling policymakers to set safe emission limits, assess health risks, and develop effective pollution reduction measures based on particle counts rather than just mass.

Question 1: Describe how the concept of the Avogadro Constant is utilised in the development of environmental sensors that detect atmospheric pollutants.

Answer: Environmental sensors often rely on chemical reactions involving a known number of particles. By calibrating sensors based on the number of particles detected and using the Avogadro Constant, accurate quantification of pollutant concentrations can be achieved, enabling real-time monitoring and better environmental management.