Which of the following statements is true about endothermic reactions?

• A. They release heat to their surroundings.
• B. They always occur spontaneously at room temperature.
• C. They absorb heat from their surroundings.
• D. The products have lower energy than the reactants.

Answer: (C)

Verified step by step guidance

1. Understand the definition of an endothermic reaction: it is a chemical reaction that absorbs heat from its surroundings during the process.
2. Recall that in an endothermic reaction, energy is taken in, so the system gains heat, meaning the surroundings lose heat.
3. Analyze the statements: 'They release heat to their surroundings' is false because releasing heat describes exothermic reactions, not endothermic ones.
4. Consider spontaneity: endothermic reactions do not always occur spontaneously at room temperature because spontaneity depends on both enthalpy and entropy changes, as described by Gibbs free energy.
5. Evaluate energy changes: in endothermic reactions, the products have higher energy than the reactants because energy is absorbed, so the statement 'The products have lower energy than the reactants' is false.