/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 9 How does the enthalpy change for... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 6: Problem 9

How does the enthalpy change for an endothermic reaction occurring at constant pressure?

Short Answer

Expert verified
The enthalpy change ( H) is positive for an endothermic reaction at constant pressure.

Step by step solution

01

Understanding Enthalpy Change

In an endothermic reaction, the system absorbs heat from the surroundings. This process results in the enthalpy change (  ... ...  ) being positive because the system's internal energy increases.
02

Defining the Sign of Enthalpy Change

Since an endothermic reaction requires energy input, the enthalpy change    ...      ( H) is greater than zero. This indicates that more energy is absorbed than is released, confirming the positive sign.
03

Applying the Constant Pressure Condition

When a reaction takes place at constant pressure, the enthalpy change ( H) is equivalent to the heat absorbed or released by the system. For an endothermic process, this means that the enthalpy change reflects the heat absorbed under these conditions.
04

Final Consideration of Energy Flow

To wrap up, under constant pressure, the energy absorbed by the system as heat in an endothermic reaction results in a positive enthalpy change (  ...  H > 0), indicating that energy flows from the surroundings into the system.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Endothermic Reaction
An endothermic reaction is a fascinating chemical process where heat is absorbed from the surroundings into the system. Imagine it as the reaction "eating" the heat to fuel its transformation.
In everyday terms, think of it like melting ice. The ice absorbs heat to change into water. It is essential for students to understand that this reaction requires energy input, hence the environment gets cooler.
Key characteristics of endothermic reactions include:
  • Heat is absorbed rather than released.
  • The surroundings become cooler as energy is drawn into the reaction.
  • The sign of the enthalpy change (\( riangle H \)) is positive.
These reactions are crucial in many natural and industrial processes, such as Photosynthesis and some types of cooking like baking bread.
Constant Pressure
In the study of chemistry, the concept of constant pressure is pivotal when discussing reactions. Constant pressure refers to a condition where the pressure remains unchanged throughout the chemical process.
This scenario is particularly significant because it relates directly to how we measure enthalpy change.
Key aspects to note about constant pressure are:
  • It simplifies the measurement of energy changes in a system.
  • Most chemical reactions occur at constant atmospheric pressure.
  • Under constant pressure, enthalpy change (\( riangle H \)) is a direct measure of heat absorbed or released.
By ensuring constant pressure, scientists can accurately assess how much heat a reaction absorbs or expels, providing clear insights into the energy dynamics involved.
Energy Absorption
Energy absorption is a fundamental concept in understanding the internal dynamics of chemical reactions. In endothermic processes, the absorption of energy is key to facilitating the reaction.
This energy is primarily stored in the form of increased chemical potential energy within the system.
Essential points about energy absorption include:
  • It increases the system's internal energy, resulting in a higher enthalpy.
  • It is the reverse of exothermic reactions, where energy is released.
  • In a laboratory setting, it can be measured as heat taken from the surroundings.
A clear understanding of energy absorption helps clarify why certain reactions only proceed at higher temperatures, as they need additional energy input to occur.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

What is meant by the thermodynamic standard state?

What is meant by the standard enthalpy of formation of a substance?

A \(10.0-\mathrm{g}\) sample of a mixture of \(\mathrm{CH}_{4}\) and \(\mathrm{C}_{2} \mathrm{H}_{4}\) reacts with oxygen at \(25^{\circ} \mathrm{C}\) and \(1 \mathrm{~atm}\) to produce \(\mathrm{CO}_{2}(\mathrm{~g})\) and \(\mathrm{H}_{2} \mathrm{O}(l)\). If the reaction produces \(520 \mathrm{~kJ}\) of heat, what is the mass percentage of \(\mathrm{CH}_{4}\) in the mixture?

Colorless nitric oxide, NO, combines with oxygen to form nitrogen dioxide, \(\mathrm{NO}_{2}\), a brown gas. $$2 \mathrm{NO}(g)+\mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{NO}_{2}(g) ; \Delta H=-114 \mathrm{~kJ}$$ What is the enthalpy change per gram of nitric oxide?

Niagara Falls has a height of \(167 \mathrm{ft}\) (American Falls). What is the potential energy in joules of \(1.00 \mathrm{lb}\) of water at the top of the falls if we take water at the bottom to have a potential energy of zero? What would be the speed of this water at the bottom of the falls if we neglect friction during the descent of the water?
See all solutions

Recommended explanations on Chemistry Textbooks

The Earths Atmosphere

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Chemistry Branches

Read Explanation

Chemical Analysis

Read Explanation

Organic Chemistry

Read Explanation

Making Measurements

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.