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href="#" class="mark-page-favorite pull-right" data-pid="889" title="Mark as favorite" onclick="return false;"><i class="fa fa-star-o"></i></a> </h1> <ol class="breadcrumb"> <li><a href="../../../chemistry.html"><i class="fa fa-home"></i></a><i class="fa fa-fw fa-chevron-right divider"></i></li><li><a href="../358/energetics.html">Energetics</a><i class="fa fa-fw fa-chevron-right divider"></i></li><li><span class="gray">Bond enthalpies</span></li> <span class="pull-right" style="color: #555" title="Suggested study time: 45 minutes"><i class="fa fa-clock-o"></i> 45'</span> </ol> <article id="main-article"> <p><img alt="" src="../../images/test-images/morse-potential-3-1.png" style="float: left; width: 160px; height: 148px;">A chemical reaction involves the breaking of bonds in reactants and the forming of bonds in products. If the energy required to break bonds in reactants is less than the energy released when bonds are formed in products, the reaction is exothermic. Conversely, if the energy required to break bonds in reactants is more than the energy released when bonds are formed in products, the reaction is endothermic.</p> <p>Bond enthalpy calculations are straight forward, but it is easy to select the wrong value (for example C-C when you need C=C) if you do not draw out the chemical structures in full.<strong> Refer to revision card 3 to help you organise your working.</strong> You should understand the importance of ozone and molecular oxygen in the atmosphere and be able to calculate the wavelengths of UV radiation needed to break the oxygen-oxygen bonds in each. <strong>Using revision card 6 as a model, practise writing out the calculation repeatedly</strong>, <strong>explaining it as you go</strong>.</p> <hr class="hidden-separator"> <div class="panel panel-has-colored-body panel-turquoise"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Key concepts</p> </div> </div> <div class="panel-body"> <div> <div class="panel-body"> <div> <p>Ensure you are confident using the terms below and learn the asterisked* definitions</p> <p>average bond enthalpy*</p> <div class="tib-flashcard"><a class="show-flashcards btn btn-success btn-xs-block btn-block " data-levels="1" data-mode="Normal" data-topics="621" data-subject-id="7" data-n-flashcards="5" style="text-align:center">Show flashcards</a></div><hr> <div class="panel panel-has-colored-body panel-has-border panel-turquoise"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Bond Enthalpy and calculations</p> </div> </div> <div class="panel-body"> <div class="video-embed vimeo"><iframe allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" mozallowfullscreen="" webkitallowfullscreen="" height="420" width="100%" src="https://player.vimeo.com/video/354223714"></iframe></div> </div> <div class="panel-footer"> <div> </div> </div> </div> </div> </div> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> <div class="panel panel-yellow panel-has-colored-body"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Essentials</p> </div> </div> <div class="panel-body"> <div> <p> The revision cards contain all of the essential content:</p> <div id="carousel-140" class="dynamic-gallery carousel slide" data-id="140"><div class="carousel-inner" role="listbox"><div class="item active"><a class="fancy" href="../../../std-galleries/7-140/screenshot-2019-09-05-at-211527.png" data-fancybox="gallery-140" title="" data-caption=""><img alt="" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211527.png"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/7-140/screenshot-2019-09-05-at-211544.png" data-fancybox="gallery-140" title="" data-caption=""><img alt="" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211544.png"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/7-140/screenshot-2019-09-05-at-211600.png" data-fancybox="gallery-140" title="" data-caption=""><img alt="" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211600.png"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/7-140/screenshot-2019-09-05-at-211618.png" data-fancybox="gallery-140" title="" data-caption=""><img alt="" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211618.png"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/7-140/screenshot-2019-09-05-at-211641.png" data-fancybox="gallery-140" title="" data-caption=""><img alt="" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211641.png"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/7-140/screenshot-2019-09-05-at-211739.png" data-fancybox="gallery-140" title="" data-caption=""><img alt="" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211739.png"></a></div></div><a class="left carousel-control" href="#carousel-140" role="button" data-slide="prev"><i class="fa fa-fw fa-chevron-left"></i></a><a class="right carousel-control" href="#carousel-140" role="button" data-slide="next"><i class="fa fa-fw fa-chevron-right"></i></a></div><ol class="std-carousel-indicators"><li data-index="0"><img title="Click to view" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211527-thumb128.jpg"><li><li data-index="1"><img title="Click to view" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211544-thumb128.jpg"><li><li data-index="2"><img title="Click to view" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211600-thumb128.jpg"><li><li data-index="3"><img title="Click to view" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211618-thumb128.jpg"><li><li data-index="4"><img title="Click to view" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211641-thumb128.jpg"><li><li data-index="5"><img title="Click to view" src="../../../std-galleries/7-140/screenshot-2019-09-05-at-211739-thumb128.jpg"><li></li></ol> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> <div class="panel panel-has-colored-body panel-green"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Test yourself</p> </div> </div> <div class="panel-body"> <div> <div class="panel-body"> <div> <div class="tib-quiz" data-stats="7-407-889"><div class="label label-default q-number">1</div><div class="exercise shadow-bottom"><div class="q-question"><p>Which of the following are correctly included in the definition of bond enthalpy?</p><p><strong>1:</strong> Bond enthalpy is an average</p><p><strong>2:</strong> Bond enthalpy is calculated for one bond</p><p><strong>3:</strong> Bond enthalpy is given in the gaseous state</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> <span>2 and 3 only</span></label> </p><p><label class="radio"> <input class="c" type="radio"> <span>1 and 3 only</span></label> </p><p><label class="radio"> <input type="radio"> <span>1,2 and 3</span></label> </p><p><label class="radio"> <input type="radio"> <span>1 only</span></label> </p></div><div class="q-explanation"><p>Bond enthalpy is defined as the <strong>average</strong> enthalpy required to break <strong>one mole</strong> of covalent bonds in the <strong>gaseous </strong>state.</p><p>Thus the correct answer is 1 and 3 only. Statement 2 suggests 'one bond' rather than one mole of bonds.</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">2</div><div class="exercise shadow-bottom"><div class="q-question"><p>Which of the following statements is correct?</p></div><div class="q-answer"><p><label class="radio"> <input class="c" type="radio"> <span>Bond breaking is endothermic and bond making is exothermic</span></label> </p><p><label class="radio"> <input type="radio"> <span>Bond making requires energy</span></label> </p><p><label class="radio"> <input type="radio"> <span>Bond breaking releases energy</span></label> </p><p><label class="radio"> <input type="radio"> <span>Bond breaking is exothermic and bond making is endothermic</span></label> </p></div><div class="q-explanation"><p>Breaking bonds requires overcoming attractive forces so bond breaking is endothermic and has a positive ΔH (requires energy input into the system). Making bonds generates attractive forces which releases energy from the system into the surroundings so is exothermic and has a negative ΔH.</p><p>Thus 'Bond breaking is endothermic and bond making is exothermic' is the correct answer.</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">3</div><div class="exercise shadow-bottom"><div class="q-question"><p>Estimate the enthalpy change (in kJ mol<sup>−1</sup>) for the following reaction using average bond enthalpies (given in the data book, and below).</p><p>2H<sub>2(g)</sub> + O<sub>2(g)</sub> → 2H<sub>2</sub>O<sub>(g)</sub></p><p>Bond enthalpies in kJ mol<sup>−1</sup> that you may require: H−H 436 / O=O 498 / O−O 144 / O−H 463</p></div><div class="q-answer"><p><label class="radio"> <input class="c" type="radio"> <span>−482</span></label> </p><p><label class="radio"> <input type="radio"> <span>+444</span></label> </p><p><label class="radio"> <input type="radio"> <span>−836</span></label> </p><p><label class="radio"> <input type="radio"> <span>−241</span></label> </p></div><div class="q-explanation"><p>Total energy change = bonds broken − bonds made</p><p>Bonds present in reactants: 2×H−H, 1×O=O</p><p>Bonds present in products: 4×O−H</p><p>(notice that there are no O−O bonds present in reactants or products)</p><p>Assuming all the bonds in reactants are broken and all bonds in products are made:</p><p>Magnitude of enthalpy for bonds broken: 2×436 + 1×498 = 1370</p><p>Magnitude of enthalpy for bonds made: 4×463 = 1852</p><p>Estimate of enthalpy change = 1370 − 1852 = −482 kJ mol<sup>−1</sup><strong><span tabindex="-1"></span></strong></p><p>Thus the correct answer is <strong>−482</strong></p><p><strong>Incorrect answers:</strong></p><p>−241 is half the value (enthalpy for one mole of water being formed).</p><p>−836 is the value obtained when 144 (O−O) is used instead of 498 (O=O).</p><p>+444 is the value obtained when 2×O−H, 926, is used instead of 4×O−H, 1852.</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">4</div><div class="exercise shadow-bottom"><div class="q-question"><p>Which of the following is likely to best represent the average bond enthalpy for the C−H bond in methane?</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> <span>CH<sub>4(g)</sub> → C<sub>(g)</sub> + 2H<sub>2(g)</sub></span></label> </p><p><label class="radio"> <input type="radio"> CH<sub>4(g)</sub> → CH<sub>3(g)</sub> + H<sub>(g)</sub> </label></p><p><label class="radio"> <input type="radio"> <span>CH<sub>4(g) </sub>→ C<sub>(g)</sub> + 4H<sub>(g)</sub></span></label> </p><p><label class="radio"> <input class="c" type="radio"> ¼<span>CH<sub>4(g)</sub> → ¼C<sub>(g)</sub> + H<sub>(g)</sub></span></label> </p></div><div class="q-explanation"><p>Average bond enthalpy is defined as the average enthalpy required to break one mole of covalent bonds in the gaseous<strong> </strong>state.</p><p>So the best representation is going to be a chemical change showing the average breaking of one mole of C−H bonds in methane the gaseous state.</p><p>CH<sub>4(g)</sub> → CH<sub>3(g)</sub> + H<sub>(g)</sub> shows a single C−H bond breaking and by definition (stoichiometric coefficients) we have one mole of methane (CH<sub>4</sub>) and thus one mole of C−H bonds breaking. But, when we break the bonds in any molecule one-by-one the bonds will all have different enthalpies as the environment of the bonds is changing.</p><p>Therefore we need to break <strong>all four bonds</strong> in methane and find the <strong>average enthalpy</strong>:</p><p>¼CH<sub>4(g)</sub> → ¼C<sub>(g)</sub> + H<sub>(g) </sub>is thus the correct answer.</p><p><strong>Incorrect answers</strong></p><p>CH<sub>4(g) </sub>→ C<sub>(g)</sub> + 4H<sub>(g)</sub> and CH<sub>4(g)</sub> → C<sub>(g)</sub> + 2H<sub>2(g)</sub> both show <strong>four </strong>moles of C−H bonds breaking, with the hydrogen products shown as atoms or molecules.</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">5</div><div class="exercise shadow-bottom"><div class="q-question"><p>Estimate the enthalpy change (in kJ mol<sup>−1</sup>) for the reaction below using average bond enthalpies (given in the data book, and below).</p><p>H<sub>2(g)</sub> + O<sub>2(g)</sub> → H<sub>2</sub>O<sub>2(g)</sub></p><p>Bond enthalpies in kJ mol<sup>−1</sup> that you may require: H−H 436 / O=O 498 / O−O 144 / O−H 463</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> <span>−844</span></label> </p><p><label class="radio"> <input class="c" type="radio"> <span>−136</span></label> </p><p><label class="radio"> <input type="radio"> <span>+8</span></label> </p><p><label class="radio"> <input type="radio"> <span>−490</span></label> </p></div><div class="q-explanation"><p>Total energy change = bonds broken − bonds made</p><p>Bonds present in reactants: 1×H−H, 1×O=O</p><p>Bonds present in products: 2×O−H, 1×O−O</p><p>Assuming all the bonds in reactants are broken and all bonds in products are made:</p><p>Magnitude of enthalpy for bonds broken: 1×436 + 1×498 = 934</p><p>Magnitude of enthalpy for bonds made: 2×463 + 1×144 = 1070</p><p>Estimate of enthalpy change = 934 − 1070 = −136 kJ mol<sup>−1</sup><strong><span tabindex="-1"></span></strong></p><p>Thus the correct answer is <strong>−136</strong></p><p><strong>Incorrect answers:</strong></p><p>−490 is the value obtained when 498 (O=O) is used instead of 144 (O−O) in the products (bonds made) or −490 is also the value obtained when 144 (O−O) is used instead of 498 (O=O) in the reactants (bonds broken).</p><p>−844 is the value obtained when 498 (O=O) is used instead of 144 (O−O) in the products (bonds made) <u>and</u> 144 (O−O) is used instead of 498 (O=O) in the reactants (bonds broken).</p><p>+8 is the value obtained when 1×O−O (144) is missing from products (bonds made), that is only 2×O−H, 926, is used.</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">6</div><div class="exercise shadow-bottom"><div class="q-question"><p>Which of the following statements best describes the action of oxygen (O<sub>2</sub>) and ozone (O<sub>3</sub>) in the atmosphere with respect to absorption of ultraviolet radiation from the sun?</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> <span>Neither oxygen nor ozone adsorb u/v radiation.</span></label> </p><p><label class="radio"> <input type="radio"> <span>Only oxygen absorbs u/v radiation.</span></label> </p><p><label class="radio"> <input class="c" type="radio"> <span>Both oxygen and ozone absorb u/v radiation.</span></label> </p><p><label class="radio"> <input type="radio"> <span>Only ozone absorbs u/v radiation.</span></label> </p></div><div class="q-explanation"><p><strong>Both oxygen and ozone absorb u/v radiation</strong> is the correct answer.</p><p>The double bond in oxygen is stronger than the '1½' bonds in ozone, but both oxygen and ozone will absorb ultraviolet radiation from the sun and the covalent bonds may break to form oxygen free radicals.</p><p>This is an important mechanism for the protection of life on the planet from the damaging (ionising) effects of ultraviolet light.</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">7</div><div class="exercise shadow-bottom"><div class="q-question"><p>Which of the following statements best describes the relationship between oxygen (O<sub>2</sub>) and ozone (O<sub>3</sub>) in the atmosphere with respect to absorption of ultraviolet radiation from the sun?</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> <span>Oxygen has weaker covalent bonds than ozone so absorbs u/v radiation of a lower wavelength.</span></label> </p><p><label class="radio"> <input type="radio"> <span>Oxygen has weaker covalent bonds than ozone so absorbs u/v radiation of a higher wavelength.</span></label> </p><p><label class="radio"> <input class="c" type="radio"> Ozone has weaker covalent bonds than oxygen so absorbs u/v radiation of a higher wavelength.<span></span></label> </p><p><label class="radio"> <input type="radio"> <span>Ozone has weaker covalent bonds than oxygen so absorbs u/v radiation of a lower wavelength.</span></label> </p></div><div class="q-explanation"><p>Both oxygen and ozone will absorb ultraviolet radiation from the sun and the covalent bonds may break to form oxygen free radicals.</p><p>The double bond in oxygen is stronger than the '1½' bonds in ozone. So it takes ultraviolet radiation of higher energy to break the bonds in oxygen than in ozone. Energy of light is inversely proportional to wavelength (higher energy = lower wavelength), so the correct answer is:</p><p><strong>Ozone has weaker bonds than oxygen so absorbs u/v radiation of a higher wavelength.</strong></p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="totals"><span class="score"></span><button class="btn btn-success btn-block text-center check-total"><i class="fa fa-check-square-o"></i> Check</button></div></div><hr> </div> </div> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> <div class="panel panel-has-colored-body panel-default"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Exam-style questions</p> </div> </div> <div class="panel-body"> <h4>Paper 1</h4> <h5>Core (SL&HL): <a href="../2708/energetics-core-sl-and-hl-paper-1-questions.html" title="Energetics core (SL and HL) paper 1 questions">Energetics core (SL and HL) paper 1 questions</a></h5> <h5>AHL (HL only): <a href="../2709/energetics-ahl-hl-only-paper-1-questions.html" title="Energetics AHL (HL only) paper 1 questions">Energetics AHL (HL only) paper 1 questions</a></h5> <h4>Paper 2</h4> <h5>Core (SL&HL): <a href="../2710/energetics-core-sl-hl-paper-2-questions.html" title="Energetics core (SL & HL) paper 2 questions">Energetics core (SL & HL) paper 2 questions</a></h5> <h5>AHL (HL only): <a href="../2711/energetics-ahl-hl-only-paper-2-questions.html" title="Energetics AHL (HL only) paper 2 questions">Energetics AHL (HL only) paper 2 questions</a></h5> </div> <div class="panel-footer"> <div> </div> </div> </div> <div class="page-container panel-self-assessment" data-id="889"> <div class="panel-heading">MY PROGRESS</div> <div class="panel-body understanding-rate"> <div class="msg"></div> <label 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}</style><div id="modal-periodic-table" class="modal fade" tabindex="-1" role="dialog"> <div class="modal-dialog modal-lg" role="document" style="width: 90vw;"> <div class="modal-content"> <div class="modal-header"> <h4 class="modal-title">Periodic table</h4> <button type="button" class="close" data-dismiss="modal" aria-label="Close"> <span aria-hidden="true">×</span> </button> </div> <div class="modal-body"> <img src="../../../img/periodic-table/periodic-table-2020.png" style="max-width: 1400px; height: auto"> </div> <div class="modal-footer"> <button type="button" class="btn btn-default btn-xs-block m-xs-0 pull-right" data-dismiss="modal" aria-hidden="true"> Close </button> </div> </div> </div></div> <div id="fc-viewer" class="modal fade modal-flashcard" tabindex="-1" role="dialog"><div class="modal-dialog" role="document"><div class="modal-content"><div class="modal-header" style="background-color: #fafafa;"><div class="row" style="width: 100%;"><div class="col-md-12 tags-heading"><div style="display: flex; justify-content: space-between; align-items: center;"><p id="fc-viewer-info" style="width: 80%;"></p><button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">×</span></button></div></div></div></div><div id="flashcard-body" class="modal-body"><div class="row" style="margin: 0;"><div class="col-md-8 fc-viewer-main"><div class="fc-viewer-inner"><div id="fc-viewer-main-front"><div class="fc-viewer-content"></div><span class="mark-favorite" style="position: absolute; top: 10px; right: 10px; font-size: 22px;"><i class="fa fa-lg fa-star-o"></i></span><span id="issue-report" class="issue-report hidden-xs hidden-sm" title="Report a problem"><i class="fa fa-fw fa-lg fa-exclamation-circle" style="font-size: 1.5em;"></i> </span> </div><div id="fc-viewer-main-back" class="reverse-flashcard green-bg"><div class="fc-viewer-content"></div><span class="mark-favorite" style="position: absolute; top: 10px; right: 10px; font-size: 22px;"><i class="fa fa-lg fa-star-o"></i></span></div></div></div><div class="col-md-4 fc-viewer-controls"><div class="fc-viewer-controls-middle"> <div class="fc-viewer-controls-middle-inner fc-back"><div class="fc-viewer-controls-answers mt-xs-0 mx-xs-0"><button id="right-answer" class="btn btn-success text-center btn-block" title="Mark this flashcard as CORRECT"><i class="fa fa-check"></i> Correct</button><button id="wrong-answer" class="btn text-center bg-red btn-block" title="Mark this flashcard as INCORRECT"><i class="fa fa-remove"></i> Incorrect</button></div><table class="table stats"><tr><td>Times flipped</td><td id="fc-viewer-tflipped" class="text-right">0</td></tr><tr><td>Marked as <em>correct</em></td><td id="fc-viewer-right" class="text-right">0</td></tr><tr><td>Marked as <em>incorrect</em></td><td id="fc-viewer-wrong" class="text-right">0</td></tr></table><a href="#" class="btn btn-default btn-sm btn-block text-center reset-stats hidden-xs hidden-sm" title="Reset stats for this flashcard" style="margin: 10px 0;"><i class="fa fa-undo"></i> Reset</a> <div class="fc-notes-container hidden-xs hidden-sm"><textarea class="form-control notes fc-back card-notes" rows="4" placeholder="Write your own notes here..." style="resize: none;">
</textarea><a href="#" class="btn btn-default btn-sm btn-block text-center save-notes" title="Save personal notes for this flashcard" style="margin-bottom: 10px;"><i class="fa fa-pencil"></i> Save notes</a> </div><div class="fc-viewer-actions-sm hidden-md hidden-lg"><button type="button" class="btn btn-sm btn-xs-block reset-stats"><i class="fa fa-fw fa-undo"></i>Reset</button> <button type="button" class="btn btn-sm btn-xs-block" data-toggle="modal" data-target="#card-notes-sm-modal"><i class="fa fa-fw fa-pencil"></i>Notes</button><button type="button" class="btn btn-sm btn-xs-block" data-toggle="modal" data-target="#report-problem-sm-modal"><i class="fa fa-fw fa-exclamation-circle"></i>Report error</button></div> </div></div><div class="fc-viewer-controls-bottom hidden-xs hidden-sm"><div class="fc-move"> <button class="btn bg-turquoise text-center disabled" rel="prev" title="Previous flashcard"><i class="fa fa-fw fa-chevron-left"></i>Prev</button><button class="btn bg-turquoise text-center disabled" rel="next" title="Next flashcard">Next<i class="fa fa-fw fa-chevron-right"></i></button></div><div class="fc-actions"><button class="btn btn-default btn-block text-center shuffle"><i class="fa fa-random"></i> Shuffle</button><div class="fc-progress"><div class="progress"><div class="progress-bar"></div></div><div class="text-right"><span class="fc-viewer-results-counter"></span></div></div></div></div><div class="fc-close-sm hidden-md hidden-lg"><button id="fc-xs-close" type="button" class="btn btn-default btn-block text-center" data-dismiss="modal" aria-label="Close">Close</button> <hr class="thin"> <div class="fc-actions" style="width: 100%;"> <button class="btn btn-default btn-block text-center shuffle"> <i class="fa fa-random"></i> Shuffle </button><div class="fc-progress"><div class="progress"><div class="progress-bar"></div></div><div class="text-right"><span class="fc-viewer-results-counter hidden-md hidden-lg"></span></div></div> </div></div></div></div></div><div class="modal-footer"><div id="report-error-container" class="report-problem"><div class="row"><div class="col-md-8"><div class="msg"></div><div class="form-group"><label>Report a problem for flashcard <span class="fc-viewer-id"></span></label><textarea class="form-control issue-description" cols="4"></textarea></div><button type="button" class="btn btn-primary pull-right send-report disabled"><i class="fa fa-paper-plane"></i>Send</button><button id="close-send-report" type="button" class="btn btn-default" style="margin-left: 0;">Close</button></div></div></div></div></div></div></div><div id="card-notes-sm-modal" class="modal fade overlay-modal" tabindex="-1" role="dialog"><div class="modal-dialog modal-sm" role="document"><div class="modal-content"><div class="modal-header p-xs-3"><h4 class="modal-title text-center my-xs-2">Notes</h4></div><div class="modal-body p-xs-3"><textarea class="form-control notes fc-back card-notes p-xs-3" rows="8" style="resize: none;">
</textarea></div><div class="modal-footer p-xs-3"><button type="button" class="btn btn-sm btn-primary btn-xs-block save-notes"><i class="fa fa-fw fa-pencil"></i>Save</button><button type="button" class="btn btn-sm btn-default btn-xs-block mx-xs-0" data-dismiss="modal" aria-label="Close">Close</button></div></div></div></div><div id="report-problem-sm-modal" class="modal fade overlay-modal report-problem" tabindex="-1" role="dialog"><div class="modal-dialog modal-sm" role="document"><div class="modal-content"><div class="modal-header p-xs-3"><h4 class="modal-title text-center my-xs-2">Report a problem for flashcard <span class="fc-viewer-id"></span></h4></div><div class="modal-body p-xs-3"><div class="msg"></div><div class="form-group mb-xs-0"><textarea class="form-control issue-description p-xs-3" rows="8"></textarea></div></div><div class="modal-footer p-xs-3"><button type="button" class="btn btn-sm btn-primary text-center btn-xs-block mb-xs-3 disabled send-report"><i class="fa fa-fw fa-paper-plane"></i>Send</button><button type="button" class="btn btn-sm btn-default text-center btn-xs-block mx-xs-0" data-dismiss="modal" aria-label="Close">Close</button></div></div></div></div> <div id="fcgame-viewer" class="modal fade modal-flashcard" tabindex="-1" role="dialog"> <div class="modal-dialog modal-lg modal-dialog-fcgame" role="document"> <div class="modal-content mc-flashcard modal-content-fcgame"> <div class="modal-header" style="background-color: #fafafa;"> <div class="row text-center" style="width: 100%;"> <div class="col-md-12"> <div style="display: flex; justify-content: space-between; align-items: center;"> <div class="text-left"> Your time: <span class="chronometer c-mobile" id="chronometer">00:00:</span> <span class="chronometer msec c-mobile" id="chronometer-msec">000</span> <br> Your best time: <span class="chronometer c-mobile" id="best-record"></span> </div> <button type="button" class="close" data-dismiss="modal" aria-label="Close"> <span aria-hidden="true">×</span> </button> </div> </div> </div> </div> <div id="fcgame-body" class=" modal-body modal-body-fcgame"> <div class="row-fluid"> <div class="col-lg-12 col-md-12 col-sm-12 fc-content" id="fc-content" style="padding: 15px;"></div> </div> </div> <div id="end-game" style="display: none;"> <div class="col-lg-10 col-lg-offset-1 col-md-10 col-md-offset-1 col-sm-10 col-sm-offset-1 result shadow-bottom"> <div id="end-game-dismiss"></div> <div id="end-game-results"></div> <div id="show-percent" style="margin-bottom: 30px;font-size: 16px;"></div> </div> <div id="end-game-fc" class="col-lg-12"></div> </div> <div id="start-game" class="col-lg-12 col-md-12 col-sm-12 centered"> <div style="width: 200px;"> <button class="btn btn-success btn-xs-block" id="play-game" style="display: block; width: 100%; margin: 10px 0;">Start</button> <button class="btn btn-default btn-xs-block" id="cancel-game" style="display: block; width: 100%; margin: 10px 0;">Cancel</button> </div> </div> <div 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