LearnChemE

.elementor-515 .elementor-element.elementor-element-4354ca8 > .elementor-container > .elementor-column > .elementor-widget-wrap{align-content:flex-start;align-items:flex-start;}.elementor-515 .elementor-element.elementor-element-4354ca8{transition:background 0.3s, border 0.3s, border-radius 0.3s, box-shadow 0.3s;margin-top:0px;margin-bottom:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-4354ca8 > .elementor-background-overlay{transition:background 0.3s, border-radius 0.3s, opacity 0.3s;}.elementor-515 .elementor-element.elementor-element-18adb6d > .elementor-element-populated{transition:background 0.3s, border 0.3s, border-radius 0.3s, box-shadow 0.3s;margin:3px 0px 0px 0px;--e-column-margin-right:0px;--e-column-margin-left:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-18adb6d > .elementor-element-populated > .elementor-background-overlay{transition:background 0.3s, border-radius 0.3s, opacity 0.3s;}.elementor-515 .elementor-element.elementor-element-79bb1c4{transition:background 0.3s, border 0.3s, border-radius 0.3s, box-shadow 0.3s;margin-top:0px;margin-bottom:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-79bb1c4 > .elementor-background-overlay{transition:background 0.3s, border-radius 0.3s, opacity 0.3s;}.elementor-bc-flex-widget .elementor-515 .elementor-element.elementor-element-cf8bb55.elementor-column .elementor-widget-wrap{align-items:center;}.elementor-515 .elementor-element.elementor-element-cf8bb55.elementor-column.elementor-element[data-element_type="column"] > .elementor-widget-wrap.elementor-element-populated{align-content:center;align-items:center;}.elementor-515 .elementor-element.elementor-element-cf8bb55 > .elementor-widget-wrap > .elementor-widget:not(.elementor-widget__width-auto):not(.elementor-widget__width-initial):not(:last-child):not(.elementor-absolute){margin-bottom:0px;}.elementor-515 .elementor-element.elementor-element-cf8bb55 > .elementor-element-populated{margin:0px 0px 0px 10px;--e-column-margin-right:0px;--e-column-margin-left:10px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-071cb4c .hfe-heading-text{color:var( --e-global-color-primary );}.elementor-515 .elementor-element.elementor-element-071cb4c .hfe-icon i{color:var( --e-global-color-primary );}.elementor-515 .elementor-element.elementor-element-071cb4c .hfe-icon svg{fill:var( --e-global-color-primary );}.elementor-bc-flex-widget .elementor-515 .elementor-element.elementor-element-5ff9494.elementor-column .elementor-widget-wrap{align-items:center;}.elementor-515 .elementor-element.elementor-element-5ff9494.elementor-column.elementor-element[data-element_type="column"] > .elementor-widget-wrap.elementor-element-populated{align-content:center;align-items:center;}.elementor-515 .elementor-element.elementor-element-5ff9494 > .elementor-element-populated{margin:0px 0px 0px 0px;--e-column-margin-right:0px;--e-column-margin-left:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-99e6049 img{width:50px;max-width:50px;}.elementor-bc-flex-widget .elementor-515 .elementor-element.elementor-element-e3a08fe.elementor-column .elementor-widget-wrap{align-items:center;}.elementor-515 .elementor-element.elementor-element-e3a08fe.elementor-column.elementor-element[data-element_type="column"] > .elementor-widget-wrap.elementor-element-populated{align-content:center;align-items:center;}.elementor-515 .elementor-element.elementor-element-e3a08fe > .elementor-element-populated{margin:0px 0px 0px 0px;--e-column-margin-right:0px;--e-column-margin-left:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-773020b{text-align:center;}.elementor-515 .elementor-element.elementor-element-773020b img{width:40px;max-width:40px;}.elementor-bc-flex-widget .elementor-515 .elementor-element.elementor-element-6bb885c.elementor-column .elementor-widget-wrap{align-items:center;}.elementor-515 .elementor-element.elementor-element-6bb885c.elementor-column.elementor-element[data-element_type="column"] > .elementor-widget-wrap.elementor-element-populated{align-content:center;align-items:center;}.elementor-515 .elementor-element.elementor-element-6bb885c > .elementor-element-populated{margin:0px 0px 0px 0px;--e-column-margin-right:0px;--e-column-margin-left:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-544e1a8 img{width:100%;max-width:45px;}.elementor-bc-flex-widget .elementor-515 .elementor-element.elementor-element-8907359.elementor-column .elementor-widget-wrap{align-items:center;}.elementor-515 .elementor-element.elementor-element-8907359.elementor-column.elementor-element[data-element_type="column"] > .elementor-widget-wrap.elementor-element-populated{align-content:center;align-items:center;}.elementor-515 .elementor-element.elementor-element-8907359 > .elementor-element-populated{margin:0px 0px 0px 0px;--e-column-margin-right:0px;--e-column-margin-left:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-ef0a165{text-align:center;}.elementor-515 .elementor-element.elementor-element-ef0a165 img{width:100%;max-width:55px;}.elementor-bc-flex-widget .elementor-515 .elementor-element.elementor-element-2acf5d2.elementor-column .elementor-widget-wrap{align-items:center;}.elementor-515 .elementor-element.elementor-element-2acf5d2.elementor-column.elementor-element[data-element_type="column"] > .elementor-widget-wrap.elementor-element-populated{align-content:center;align-items:center;}.elementor-515 .elementor-element.elementor-element-2acf5d2.elementor-column > .elementor-widget-wrap{justify-content:flex-end;}.elementor-515 .elementor-element.elementor-element-2acf5d2 > .elementor-element-populated{margin:0px 0px 0px 0px;--e-column-margin-right:0px;--e-column-margin-left:0px;padding:0px 0px 0px 08px;}.elementor-515 .elementor-element.elementor-element-5a21732{text-align:left;}.elementor-515 .elementor-element.elementor-element-5a21732 img{width:100%;max-width:350px;}.elementor-515 .elementor-element.elementor-element-54633e8 > .elementor-container{min-height:0px;}.elementor-515 .elementor-element.elementor-element-54633e8{transition:background 0.3s, border 0.3s, border-radius 0.3s, box-shadow 0.3s;margin-top:0px;margin-bottom:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-54633e8 > .elementor-background-overlay{transition:background 0.3s, border-radius 0.3s, opacity 0.3s;}.elementor-515 .elementor-element.elementor-element-ff739e6 > .elementor-element-populated{margin:0px 0px 0px 0px;--e-column-margin-right:0px;--e-column-margin-left:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-nav-menu__toggle{margin:0 auto;}.elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-menu-item{padding-left:12px;padding-right:12px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-sub-menu-item{padding-left:calc( 12px + 20px );padding-right:12px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-nav-menu__layout-vertical .menu-item ul ul a.hfe-sub-menu-item{padding-left:calc( 12px + 40px );padding-right:12px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-nav-menu__layout-vertical .menu-item ul ul ul a.hfe-sub-menu-item{padding-left:calc( 12px + 60px );padding-right:12px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-nav-menu__layout-vertical .menu-item ul ul ul ul a.hfe-sub-menu-item{padding-left:calc( 12px + 80px );padding-right:12px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-sub-menu-item{padding-top:15px;padding-bottom:15px;}.elementor-515 .elementor-element.elementor-element-5b5f33e a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e a.hfe-sub-menu-item{font-size:1rem;}.elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu a.hfe-sub-menu-item{color:var( --e-global-color-primary );}.elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-menu-item:hover, .elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu a.hfe-sub-menu-item:hover, .elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item.current-menu-item a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-menu-item.highlighted, .elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-menu-item:focus{color:#CFB87C;}.elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item.current-menu-item a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item.current-menu-ancestor a.hfe-menu-item{color:#0377BD;}.elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown .menu-item a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown .menu-item a.hfe-sub-menu-item{background-color:#fff;} .elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu li a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li a.hfe-sub-menu-item{font-size:0.9rem;}.elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-nav-menu__layout-horizontal .sub-menu, .elementor-515 .elementor-element.elementor-element-5b5f33e nav:not(.hfe-nav-menu__layout-horizontal) .sub-menu.sub-menu-open, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown .hfe-nav-menu, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible .hfe-nav-menu{border-style:solid;border-width:1px 1px 1px 1px;border-color:#C4C4C4;}.elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu{border-radius:2px 2px 2px 2px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu li.menu-item:first-child{border-top-left-radius:2px;border-top-right-radius:2px;overflow:hidden;}.elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu li.menu-item:last-child{border-bottom-right-radius:2px;border-bottom-left-radius:2px;overflow:hidden;}.elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown{border-radius:2px 2px 2px 2px;}.elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li.menu-item:first-child{border-top-left-radius:2px;border-top-right-radius:2px;overflow:hidden;}.elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li.menu-item:last-child{border-bottom-right-radius:2px;border-bottom-left-radius:2px;overflow:hidden;}.elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible{border-radius:2px 2px 2px 2px;}.elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li.menu-item:first-child{border-top-left-radius:2px;border-top-right-radius:2px;overflow:hidden;}.elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li.menu-item:last-child{border-bottom-right-radius:2px;border-bottom-left-radius:2px;overflow:hidden;}.elementor-515 .elementor-element.elementor-element-5b5f33e ul.sub-menu{width:262px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu li a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li a.hfe-menu-item{padding-left:8px;padding-right:8px;}.elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li a.hfe-sub-menu-item{padding-left:calc( 8px + 20px );padding-right:8px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-dropdown .menu-item ul ul a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-dropdown-expandible .menu-item ul ul a.hfe-sub-menu-item{padding-left:calc( 8px + 40px );padding-right:8px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-dropdown .menu-item ul ul ul a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-dropdown-expandible .menu-item ul ul ul a.hfe-sub-menu-item{padding-left:calc( 8px + 60px );padding-right:8px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-dropdown .menu-item ul ul ul ul a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e .hfe-dropdown-expandible .menu-item ul ul ul ul a.hfe-sub-menu-item{padding-left:calc( 8px + 80px );padding-right:8px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li a.hfe-sub-menu-item{padding-top:8px;padding-bottom:8px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu li.menu-item:not(:last-child), .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li.menu-item:not(:last-child), .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li.menu-item:not(:last-child){border-bottom-style:solid;border-bottom-color:#c4c4c4;border-bottom-width:1px;}.elementor-515 .elementor-element.elementor-element-6badb1b{margin-top:0px;margin-bottom:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-954b0da > .elementor-widget-wrap > .elementor-widget:not(.elementor-widget__width-auto):not(.elementor-widget__width-initial):not(:last-child):not(.elementor-absolute){margin-bottom:0px;}.elementor-515 .elementor-element.elementor-element-954b0da > .elementor-element-populated{margin:0px 0px 0px 0px;--e-column-margin-right:0px;--e-column-margin-left:0px;padding:0px 0px 0px 0px;}.elementor-515 .elementor-element.elementor-element-15d435d > .elementor-widget-container{margin:0px 0px 0px 0px;padding:0px 0px 0px 0px;}@media(max-width:1024px){.elementor-515 .elementor-element.elementor-element-071cb4c .hfe-heading{text-align:left;}.elementor-515 .elementor-element.elementor-element-99e6049 img{max-width:45px;}.elementor-515 .elementor-element.elementor-element-773020b img{max-width:45px;}.elementor-515 .elementor-element.elementor-element-544e1a8 img{max-width:45px;}.elementor-515 .elementor-element.elementor-element-ef0a165 img{max-width:56px;}.elementor-bc-flex-widget .elementor-515 .elementor-element.elementor-element-2acf5d2.elementor-column .elementor-widget-wrap{align-items:center;}.elementor-515 .elementor-element.elementor-element-2acf5d2.elementor-column.elementor-element[data-element_type="column"] > .elementor-widget-wrap.elementor-element-populated{align-content:center;align-items:center;}.elementor-515 .elementor-element.elementor-element-54633e8 > .elementor-container{min-height:0px;}.elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e .menu-item a.hfe-sub-menu-item{padding-top:5px;padding-bottom:5px;}.elementor-515 .elementor-element.elementor-element-5b5f33e a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e a.hfe-sub-menu-item{font-size:0.95rem;}.elementor-515 .elementor-element.elementor-element-5b5f33e .sub-menu a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown li a.hfe-sub-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li a.hfe-menu-item, .elementor-515 .elementor-element.elementor-element-5b5f33e nav.hfe-dropdown-expandible li a.hfe-sub-menu-item{padding-top:8px;padding-bottom:8px;}}@media(min-width:768px){.elementor-515 .elementor-element.elementor-element-cf8bb55{width:36%;}.elementor-515 .elementor-element.elementor-element-5ff9494{width:7%;}.elementor-515 .elementor-element.elementor-element-e3a08fe{width:7%;}.elementor-515 .elementor-element.elementor-element-6bb885c{width:7%;}.elementor-515 .elementor-element.elementor-element-8907359{width:7.33%;}.elementor-515 .elementor-element.elementor-element-2acf5d2{width:35%;}}@media(max-width:1024px) and (min-width:768px){.elementor-515 .elementor-element.elementor-element-cf8bb55{width:38%;}.elementor-515 .elementor-element.elementor-element-5ff9494{width:6%;}.elementor-515 .elementor-element.elementor-element-e3a08fe{width:7%;}.elementor-515 .elementor-element.elementor-element-6bb885c{width:7%;}.elementor-515 .elementor-element.elementor-element-8907359{width:9%;}.elementor-515 .elementor-element.elementor-element-2acf5d2{width:33%;}}@media(max-width:767px){.elementor-515 .elementor-element.elementor-element-cf8bb55{width:100%;}.elementor-515 .elementor-element.elementor-element-071cb4c .elementor-heading-title, .elementor-515 .elementor-element.elementor-element-071cb4c .hfe-heading a{font-size:2rem;}.elementor-515 .elementor-element.elementor-element-5ff9494{width:3%;}.elementor-515 .elementor-element.elementor-element-e3a08fe{width:3%;}.elementor-515 .elementor-element.elementor-element-6bb885c{width:3%;}.elementor-515 .elementor-element.elementor-element-8907359{width:3%;}.elementor-515 .elementor-element.elementor-element-2acf5d2{width:100%;}.elementor-515 .elementor-element.elementor-element-2acf5d2 > .elementor-element-populated{padding:5px 5px 5px 5px;}.elementor-515 .elementor-element.elementor-element-5a21732 img{max-width:237px;}.elementor-515 .elementor-element.elementor-element-54633e8 > .elementor-container{min-height:50px;}.elementor-515 .elementor-element.elementor-element-5b5f33e > .elementor-widget-container{margin:0px 0px 0px 0px;padding:0px 0px 0px 0px;}}

Gas-Phase Chemical Equilibrium: Summary

The answers to the ConcepTests are given below and will open in a separate window. 
Key points from this module:
  • The equilibrium constant is dimensionless and is independent of pressure, but not of temperature.
  • The equilibrium composition is only independent of pressure if the number of gas-phase moles does not change in the reaction and the gases are ideal. If the number of gas-phase moles in the reaction increases, increasing the pressure at constant temperature decreases the equilibrium conversion. If the number of gas-phase moles in the reaction decreases, increasing the pressure at constant temperature increases the equilibrium conversion.
  • An inert gas can change the equilibrium conversion if the reaction involves a change in the number of gas-phase moles. If the number of gas-phase moles in the reaction increases, adding an inert gas at constant temperature and pressure increases equilibrium conversion (the same as decreasing the pressure). If the number of gas-phase moles in the reaction decreases, adding an inert at constant temperature and pressure decreases equilibrium conversion (the same as increasing the pressure).
  • For an exothermic reaction (ΔH < 0), as temperature increases, K decreases.
  • For an endothermic reaction (ΔH > 0), as temperature increases, K increases.
From studying this module, you should now be able to:
  • Express equilibrium constants in terms of thermodynamic activities.
  • Explain why the chemical equilibrium constant is dimensionless.
  • Explain why the equilibrium constant is independent of pressure.
  • Calculate heat of reaction at 298 K from heats of formation.
  • Calculate how the equilibrium constant changes with temperature.
  • Calculate the standard Gibbs free energy change for a reaction at 298 K, and its equilibrium constant, from Gibbs free energies of formation.
  • Calculate equilibrium conversions.
  • Explain why pressures must be in bar in equilibrium calculations.
  • Describe how equilibrium constants change with temperature for endothermic and exothermic reactions.
  • Calculate equilibrium mole fraction for ideal gases and non-ideal gases.
  • Predict how pressure changes will shift equilibrium conversion for a gas-phase reaction with a mole change.
  • Predict how an addition of an inert will affect equilibrium conversion.

 

Prepared by John L. Falconer, Department of Chemical and Biological Engineering, University of Colorado Boulder