Question #5304e
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"How do you calculate the Gibbs Free Energy change of a reaction?"
#E_P=mgh#
Where #E_P# is the potential energy
#m# is mass in kilograms
#g# is the acceleration of gravity on Earth
#h# is the height above ground (reference point)
Using the units given, you can identify that you have the mass and potential energy, and need height. Plug these numbers into the formula.
#70J=2kg*9.8m/s^2*h#
Simplifying the right-hand side gives #70J=19.6(kg*m)/s^2*h#
Divide both sides by 19.6 kilograms meters per second squared on both sides of the equation to get the height.
#3.57m=h#
#GPE = mgh#
where #m# is mass, in #kg#
#g# is gravitational field strength, in #N//kg#
#h# is height, in #m#.
#h = (GPE)/(mg)#
#m = 2kg#
#g ~~ 9.81# (assuming that the question is set on Earth)
#GPE = 70J#
#(GPE)/(mg) = 70/(2*9.81)#
#=70/19.62#
#h = 70/19.62#
#= 3.57m# (3s.f.)
note: if you want to use #10N//kg# for the value of #g#, the method is the same. the answer obtained is #7/2#, which is #3.5m#.
