In thermochemistry, during which type of change is energy absorbed from the surroundings by the system?

Introduction / Context:
In thermochemistry and physical chemistry, chemical and physical changes are classified based on whether they release energy to the surroundings or absorb energy from the surroundings. These ideas are crucial for understanding reaction energetics, enthalpy changes, and everyday phenomena such as melting ice or burning fuel. This question asks you to identify the type of change in which energy is absorbed by the system from its surroundings.

Given Data / Assumptions:

• The key terms are exothermic and endothermic changes.
• Exothermic processes release energy, often as heat, to the surroundings.
• Endothermic processes absorb energy, usually as heat, from the surroundings.
• We assume the usual convention where the system is the reacting or changing material.

Concept / Approach:
An exothermic change is one in which the system loses energy to the surroundings; examples include combustion reactions and many neutralization reactions. An endothermic change is one in which the system gains energy from the surroundings; examples include melting of ice, evaporation of water, and some decomposition reactions. The question specifically asks about energy being absorbed from the surroundings by the system, which matches the definition of an endothermic change. Therefore, the correct answer is endothermic change.

Step-by-Step Solution:
Step 1: Recall that in an exothermic process, heat flows from the system to the surroundings, making the surroundings warmer. Step 2: Recall that in an endothermic process, heat flows from the surroundings into the system, making the surroundings cooler. Step 3: Interpret the phrase “energy is absorbed from the surroundings by the system” as describing an endothermic situation. Step 4: Compare this interpretation with the definitions and confirm that exothermic processes do the opposite, releasing instead of absorbing energy. Step 5: Select “endothermic change” as the correct answer.

Verification / Alternative check:
Consider familiar examples: when ice melts, it feels cold to the touch because it absorbs heat from your hand and the environment; this is an endothermic process. When water boils, heat is absorbed from the stove or heater by the water, again indicating an endothermic change. On the other hand, when a candle burns, heat is released to the surroundings and the flame feels warm, showing an exothermic process. These real life examples reinforce the idea that the process which absorbs energy from the surroundings is endothermic, matching the option given in the question.

Why Other Options Are Wrong:
Exothermic changes release energy to the surroundings, so they are the opposite of what the question describes. The option claiming that both exothermic and endothermic changes absorb energy is incorrect because only endothermic processes absorb net energy from the surroundings, while exothermic processes release net energy. The suggestion that neither type of change absorbs energy ignores the definition of endothermic changes and is therefore incorrect. Only the endothermic option accurately matches the description provided in the question.

Common Pitfalls:
A common mistake is to confuse the terms exothermic and endothermic because they sound similar or to remember them based only on whether temperature seems to increase or decrease. Another pitfall is to forget that the key is the direction of energy transfer relative to the system, not just whether the surroundings feel hot or cold. To avoid confusion, remember the simple associations: “exo” means out (energy leaving the system), and “endo” means in (energy entering the system). This helps you quickly determine which kind of process is being described in exam questions.

Final Answer:
Energy is absorbed from the surroundings by the system during an endothermic change.