Question

read the passage about three more slow processes of the carbon cycle: fossil fuel formation, fossil fuel combustion, and volcanic activity. fossil fuel formation occurs when ancient plants, plankton, and algae that have been buried deep underground experience enormous heat and pressure. over millions of years, they are transformed into fossil fuels like coal, petroleum, and natural gas. humans extract fossil fuels and burn them for energy. when fossil fuels burn, they undergo a chemical reaction known as combustion. during a combustion reaction, a carbon - based fuel source, like the methane found in natural gas, reacts with oxygen gas (o₂) in the air to produce carbon dioxide gas (co₂) and water vapor (h₂o). this reaction releases heat energy, which humans use to power vehicle engines and to generate electricity at power plants. volcanic activity also releases carbon stored below earths surface into the atmosphere. when they erupt, volcanoes release lava, ash, and gases, including co₂. over earths history, volcanic activity has emitted a large amount of co₂ into the atmosphere. however, the amount of co₂ emitted by volcanoes each year is small compared to the amount emitted by fossil fuel combustion. for example, the 1980 eruption of mount saint helens in washington state released 10 million tons of co₂ into the atmosphere over 9 hours. by comparison, human activities emit that same amount of co₂ in just 2.5 hours. identify each substance as a reactant or product of a combustion reaction.

Explanation:

Step1: Recall combustion reaction concept

A combustion reaction is a chemical reaction where a carbon - based fuel reacts with oxygen. Reactants are substances that start the reaction, and products are substances formed.

Step2: Identify oxygen

Oxygen ($O_2$) is a reactant as it reacts with the carbon - based fuel.

Step3: Identify carbon - based fuel

The carbon - based fuel is a reactant as it is consumed in the reaction with oxygen.

Step4: Identify carbon dioxide

Carbon dioxide ($CO_2$) is a product formed from the reaction of carbon - based fuel and oxygen.

Step5: Identify water vapor

Water vapor ($H_2O$) is a product formed from the reaction of carbon - based fuel and oxygen.

Answer:

Oxygen: Reactant
Carbon - based fuel: Reactant
Carbon dioxide: Product
Water vapor: Product