An endothermic reaction becomes exothermic when a catalyst is added into the reaction mixture.

Question

BlackTom AI · Accepted Answer

Consider the statement: 'An endothermic reaction becomes exothermic when a catalyst is added into the reaction mixture.'
Option 1: True. This option asserts that a catalyst can flip the heat flow direction of a reaction. In reality, catalysts do not alter the overall enthalpy change (ΔH) of a reaction; they only provide an alternative reaction pathway with a lower activation energy. Therefore, the thermodynamic character of the reaction—whether it is endothermic or exothermic—remains unchanged by the presence of a catalyst.
Option 2: False. This is the correct characterization of how catalysts work. A catalyst increases the rate at which equilibrium is reached (or the rate of conversion) by lowering the activation energy of the reaction, but it does not change the total energy absorbed or released during the process. Consequently, an endothermic reaction stays endothermic, and an exothermic reaction stays exothermic, with or without a catalyst. It only speeds up the rate, not the thermodynamic outcome.
Additional nuance: If temperature changes accompany catalysis in a system, you might observe different reaction rates or shifts in equilibrium positions due to temperature dependencies, but the fundamental ΔH of the reaction path remains the same. The catalyst cannot convert an endothermic process into an exothermic one, nor vice versa.

CHM1051 MUM S1 2025 Week 12: Weekly quiz (1%)

An endothermic reaction becomes exothermic when a catalyst is added into the reaction mixture.

查看解析

登录即可查看完整答案

类似问题

Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst?

Which one of the following was described in the video as being a 'hallmark' of being a catalyst?

When a catalyst is used in a reaction,

A catalyst alters the rate of a chemical reaction by

What is a main use of platinum group metals?

The effect of a catalyst on a reaction is to ________.

In a consumer society, many adults channel creativity into buying things

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单