Which statement about energy and combustion is accurate?

• A. Combustion reactions are exothermic and release energy in the form of heat.
• B. Combustion reactions only occur at room temperature and do not release heat.
• C. Combustion reactions absorb energy from the surroundings and are endothermic.
• D. Combustion reactions do not involve any energy change.

Answer: (A)

Verified step by step guidance

1. Understand the definition of combustion reactions: Combustion is a chemical reaction where a substance (usually a hydrocarbon) reacts with oxygen to produce carbon dioxide, water, and energy.
2. Recall the energy changes in chemical reactions: Exothermic reactions release energy to the surroundings, often as heat, while endothermic reactions absorb energy from the surroundings.
3. Analyze the nature of combustion reactions: Since combustion produces heat and light, it must be releasing energy, indicating it is an exothermic process.
4. Evaluate the given statements based on this understanding: The statement that combustion reactions are exothermic and release energy in the form of heat aligns with the definition and characteristics of combustion.
5. Conclude that combustion reactions do not occur only at room temperature, do not absorb energy (endothermic), and do involve energy changes, so those statements are inaccurate.