bond enthalpies

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305174946
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Joined: Fri Sep 28, 2018 12:17 am

bond enthalpies

Postby 305174946 » Fri Jan 25, 2019 11:45 am

Will the values for bond enthalpies between atoms always be positive?

Samantha Kwock 1D
Posts: 61
Joined: Fri Sep 28, 2018 12:24 am

Re: bond enthalpies

Postby Samantha Kwock 1D » Fri Jan 25, 2019 2:11 pm

The values for bond enthalpy will always be given as a positive value. However, if bonds are being formed instead of broken, then this value will take on a negative sign to indicate this.

Ray Guo 4C
Posts: 90
Joined: Fri Sep 28, 2018 12:15 am

Re: bond enthalpies

Postby Ray Guo 4C » Fri Jan 25, 2019 3:42 pm

Yes, because breaking a bond is always endothermic.

Michael Novelo 4G
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Joined: Fri Sep 28, 2018 12:28 am

Re: bond enthalpies

Postby Michael Novelo 4G » Fri Jan 25, 2019 4:29 pm

Yes and when solving its Reactants minus the products where the Reactants are always a positive value since there is bond breaking and products are negative since binds are formed.

Stevin1H
Posts: 89
Joined: Fri Sep 28, 2018 12:17 am

Re: bond enthalpies

Postby Stevin1H » Thu Jan 31, 2019 1:07 am

Bond enthalpies between atoms will be positive when bonds are being broken because energy is required in order to break the bond (this is an endothermic process). However, when bonds are being formed, energy is released (exothermic process) and we account for this by including a negative in front of the bond enthalpy values.

megan blatt 2B
Posts: 61
Joined: Fri Sep 28, 2018 12:28 am

Re: bond enthalpies

Postby megan blatt 2B » Thu Jan 31, 2019 3:25 pm

The enthalpies of bonds always begin as positive values. The sign will only change depending on whether the bond is being broken or formed. The formula for calculating bond enthalpies is bonds broken - bonds formed because breaking bonds requires adding energy and is an endothermic process (positive delta H) and forming bonds releases energy and is therefore exothermic (negative delta H).


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