11.
on an atomic scale, how does the strength of electric force compare to the stren
gravitational force?
a electric force is equal to gravitational force,
b. gravitational force is stronger than electric force.
c. electric force is stronger than gravitational force,
d. scientists have not vet determined which force is stronger.

8.29 two streams containing pyridine and acetic acid at 25°c are mixed and fed into a heat exchanger. due to the heat-of-mixing effect, it is desired to reduce the temperature after mixing to 25°c using a stream of chilled ethylene glycol as indicated in the diagram. calculate the mass flow rate of ethylene glycol needed. the heat capacity of ethylene glycol at these conditions is approximately 2.8 kj/(kg k), and the enthalpy change of mixing (δmixh) is given below.