The question states: "Which of following changes that affect the composition of our atmosphere involve physical changes and which involve chemical reactions?"
Then the question lists 6 different scenarios and I have to sort them into either "chemical reaction" or "physical change".
Two of the the scenarios are:
"human activities such as the combustion of fossil fuels has increased the levels of greenhouse gases."
"human activities such as the combustion of fossil fuels generate aerosols."
The Attempt at a Solution
I realize that combustion is always a chemical change, but when they list two effects of it, that's what confusing me. Is the question asking whether the combustion of fossil fuels is chemical or physical, or is it asking whether increased greenhouse gases and the generation of aerosols are chemical or physical? thanks