. This move involves exactly what it sounds like – banging your head up and down like a madman. This dance move is most performed during hard rock songs with heavy guitar riffs.  Make sure you stay stationary while headbanging. Leave yourself plenty of room if you are headbanging near other people. You don’t want to headbutt anyone and injure them, or yourself. Don’t headbang too hard. It’s easy to throw out your neck or back muscles while rocking out. . Moshing occurs most during hardcore rock songs, punk and in heavy metal music.  Just about anyone can do it! All dancers gather in one area (called the mosh pit) and jump up and down, bounding off one another.  There’s a good chance this may not be allowed at your school. Moshing is very physical and dangerous, so get involved at your own risk. If someone you are Moshing with falls down or gets hurt, help them up. Falling down in a mosh pit is dangerous and it's hard to notice when someone gets in over their head. . Breakdancing is a physically intense dance that requires a lot of upper body strength, agility, and skill. Songs with fast hip hop beats are most commonly associated with breakdancing. If you want to breakdance at the school dance, be prepared for lots of practice beforehand.  Start at the beginning. Learn the most basic breakdance moves first. Once you have these down, you can start moving on to the harder dance moves, such as transitions and power moves. Stretch before you start breakdancing. Like head banging, breakdancing is physically demanding. You don’t want to be carried out of the school dance on a stretch. Give yourself plenty of room. Breakdancing at high levels involves a whirlwind of legs and arms. Don’t clobber a classmate or teacher with your sweet dance moves. . Freestyle or club dancing involves following your gut and the rhythm – you just make up the moves as you go along. This can include arm, head, torso, and leg movements. Freestyle is great for any kind of music. After all, you’re making the moves.  Just keep moving. There is no right or wrong way to freestyle. Move to the rhythm. Find music that sparks your creativity. Turn on the music at home and dance in your room. Find the music that gets you moving and inspires you to take chances on the dance floor. The snap dance is a mellow dance often performed during R&B and other smooth songs. Mix it up with some slow freestyle to keep the rhythm going. Move one shoulder forward and one shoulder backwards in a back and forth motion. Keep one shoulder stationary and then bend one knee and rock to the opposite side at an angled motion. Rock back to the original position while snapping your fingers. Now you’re snap dancing! These dances involve a whole line of people doing the same exact choreographed moves. Examples of these dances include the Macarena, the Cha Cha Slide, and the Electric Slide.  If you don't know the motions, you can sit that one out to observe the moves, and then give it a try on the next play. Feel free to jump in the line even if you don’t know the moves. Choreographed dances are more about silly fun than showing off your serious dance skills. Some country dances fall under this category, such as line or square dancing. Techno and similar electronic music are a mainstay at clubs and you might just hear a song or two at your school dance. Elaborate hand motions and smooth body gyrations are the go to moves for slower techno. Faster techno dancing involves sharp movements of the joints.  For a slow techno dance, try the Flower. Open your palms with your wrists together and move them around like you are molding a bowl out of clay. Roll your wrists together so that the back of your wrists are facing one another. Finally, roll your palms back so they are facing one another, and start over. Faster techno and Eurodance lends itself well to freestyle dancing. When in doubt, follow your sense of rhythm.

Summary: Get your headbanging down Jump into the mosh pit Check out the latest breakdance moves Practice your freestyle Slow roll it with snap dance. Study a few choreographed dances. Come up with a gameplan for less popular music.


There are many tables that have information on the average bond energies for a specific bond. These tables can be found online or in a chemistry book. It is important to note that these bond energies are always for molecules in a gaseous state.  For our example, you need to find the bond energy for an H-H bond, a Br-Br bond, and an H-Br bond. H-H = 436 kJ/mol; Br-Br = 193 kJ/mol; H-Br = 366 kJ/mol.  To calculate bond energy for molecules in a liquid state, you need to also look up the enthalpy change of vaporization for the liquid molecule. This is the amount of energy needed to convert the liquid into a gas. This number is added to the total bond energy. For example: If you were given liquid water, you would need to add the enthalpy change of vaporization of water (+41 kJ) to the equation. In some equations, you may have the same bond broken multiple times. For example, if 4 atoms of hydrogen are in the molecule, then the bond energy of hydrogen must be counted 4 times, or multiplied by 4.  In our example, there is only 1 bond of each molecule, so the bond energies are simply multiplied by 1. H-H = 436 x 1 = 436 kJ/mol Br-Br = 193 x 1 = 193 kJ/mol Once you have multiplied the bond energies by the number of the individual bonds, you need to then sum all of the bonds on the reactant side. For our example, the sum of the bonds broken is H-H + Br-Br = 436 + 193 = 629 kJ/mol. Just as you did for the bonds broken on the reactant side, you will multiply the number of bonds formed by its respective bond energy. If you have 4 hydrogen bonds formed, you would need to multiply that bond energy by 4. For our example we have 2 H-Br bonds formed, so the bond energy of H-Br (366 kJ/mol) will be multiplied by 2: 366 x 2 = 732 kJ/mol. Again, like you did with the bonds broken, you will add up all of the bonds formed on the product side. Sometimes you will only have 1 product formed and can skip this step. In our example, there is only 1 product formed, so the energy of the bonds formed is simply the energy of the 2 H-Br bonds or 732 kJ/mol. Once you have summed all of the bond energies for both sides, simply subtract the formed bonds from the broken bonds. Remember the equation: ΔH = ∑H(bonds broken) - ∑H(bonds formed). Plug in the calculated values and subtract. For our example: ΔH = ∑H(bonds broken) - ∑H(bonds formed) = 629 kJ/mol - 732 kJ/mol = -103 kJ/mol. The final step to calculating bond energy is to determine whether the reaction releases energy or consumes energy. An endothermic (one that consumes energy) will have a final bond energy that is positive, while an exothermic reaction (one that releases energy) will have a negative bond energy. In our example, the final bond energy is negative, therefore, the reaction is exothermic.
Summary: Look up the bond energies of the bonds in question. Multiply the bond energies by the number of bonds broken. Add up all of the bond energies of the broken bonds. Multiply the bond energies by the number of bonds formed. Add up all of the formed bond energies. Subtract the formed bonds from the broken bonds. Determine whether the entire reaction was endothermic or exothermic.