Question 1: Define 'carbon footprint' and explain its significance in assessing environmental impact.

Answer: A carbon footprint is the total amount of greenhouse gases, primarily carbon dioxide, emitted directly or indirectly by human activities. It is significant because it helps quantify individual or organisational contributions to climate change.

Question 1: Describe how burning fossil fuels increases the concentration of greenhouse gases in the atmosphere.

Answer: Burning fossil fuels releases carbon dioxide and other greenhouse gases into the atmosphere, increasing their concentration, which enhances the greenhouse effect and leads to global warming.

Question 1: Calculate the amount of CO₂ emitted when 10 litres of petrol (density 0.75 kg/L, combustion releases 2.31 kg CO₂ per kg petrol) is burnt. Show your working.

Answer: The mass of petrol = 10 L × 0.75 kg/L = 7.5 kg; CO₂ emitted = 7.5 kg × 2.31 kg CO₂/kg petrol = 17.33 kg CO₂.

Question 1: Design a basic experimental approach to determine the source of carbon dioxide found at a crime scene suspected to be from combustion. List the key variables and safety precautions.

Answer: Approach: Collect atmospheric samples from the scene, analyse the isotopic ratio of carbon (¹²C/¹³C) using mass spectrometry to distinguish between fossil fuel combustion and biogenic sources. Variables include sample location, time, and collection methods. Safety precautions involve wearing gloves, avoiding contamination, and handling chemicals with care.

Question 1: A forensic report states that atmospheric CO₂ levels at a site are 20% higher than average background levels. What could this indicate about local human activity, and how might this relate to a carbon footprint?

Answer: The elevated CO₂ levels suggest increased local combustion activities, such as vehicle emissions or industrial processes, contributing to a higher carbon footprint in that area.

Question 1: Suggest two technological measures industries can adopt to reduce their carbon footprint and explain their scientific basis.

Answer: Industries can implement carbon capture and storage (CCS) to trap CO₂ emissions before release, and switch to renewable energy sources like wind or solar power, which produce no greenhouse gases during operation.

Question 1: Discuss how analysing the isotopic signature of carbon in atmospheric samples can help trace pollution sources.

Answer: Different sources of carbon have distinct isotopic signatures. By analysing these, forensic scientists can identify whether CO₂ originated from fossil fuels, biomass burning, or other sources, aiding environmental investigations.

Question 1: Describe how individual choices, such as using public transport or adopting renewable energy, can impact forensic investigations related to atmospheric pollution.

Answer: Individual choices that reduce greenhouse gas emissions lower atmospheric CO₂ levels, which can be detected and used in forensic investigations to assess sources and contributions of pollution.