Chem Notes 112210 - ±o get the ΔΗrxn you can use bonding...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Chemical Bonds—Real Physical Properties Bond Energy: How much energy it takes to pull a bond apart, ex. Cl2 (g) 2Cl (g), ΔH = +243 kJ, the change in enthalpy is the bond strength. Bonds energies are always positive. This is mainly done with covalent bonds, because by ionic bonds we’re going to have to deal with lattice energies in order to understand the strength of the bond. Single/double/triple bonds: Ex. N—N 163 kJ/mol, N=N is 418 kJ/mol, and N(triple bond)N is 946 kJ/mol, meaning that higher bonds mean more bond energy. Distance also is affected by more bonds—with a stronger bond, the distance between the two atoms gets smaller, but only with similar parts—other things come into account when there are two different atoms.
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ±o get the ΔΗrxn, you can use bonding energy of product – reactant, = ΣΔΗbroken – ΣΔΗformed.--ex. H3C—H + Cl2 H3C—Cl + H—Cl--you see there is a broken CH and Cl Cl on the le³, and on the right there’s CCl and HCl. So you add up the ones on the le³ and subtract them from the ones on the right. So here it’s (414 + 243) – (339 + 431) = -113 kJ/mol. ±his number is comparable to using the standard enthalpy of formaTon. Bonding in MeTals Nothing really applies from what we’ve seen before, like Lewis structures, because everything literally right next to each other, and that’s why metals are so good at conducTng things— electricity can just ´y from one side to the other without waiTng around....
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern