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bond enthalpies

Posted: Fri Jan 25, 2019 11:45 am
by 305174946
Will the values for bond enthalpies between atoms always be positive?

Re: bond enthalpies

Posted: Fri Jan 25, 2019 2:11 pm
by Samantha Kwock 1D
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.

Re: bond enthalpies

Posted: Fri Jan 25, 2019 3:42 pm
by Ray Guo 4C
Yes, because breaking a bond is always endothermic.

Re: bond enthalpies

Posted: Fri Jan 25, 2019 4:29 pm
by Michael Novelo 4G
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.

Re: bond enthalpies

Posted: Thu Jan 31, 2019 1:07 am
by Stevin1H
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.

Re: bond enthalpies

Posted: Thu Jan 31, 2019 3:25 pm
by megan blatt 2B
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).