What will be the coefficient k.

The removal efficiency of a reactor tank is 73-percent and its residence time is 28.5s. For steady flow and first-order kinetics what will be the reaction for the coefficient(k) for the tank.

Flow in a pipe using conservation of mass, energy momentum and loss

I have attached a copy of the problem I need help with. Its not that complicated and i think I actually did it last semester but I cant remember how.I need all of the equations set up step by step so I can understand how to set them up

Tee flow no friction, change in density 1-D

Please see the attached file for full problem description.

Finding the volume of hydrogen

A hydrogen filled balloon of the type used in cosmic ray studies is to be expanded to its full size which is a 100-ft diameter sphere, without stress in the wall at an altitude of 150,000 ft. If the pressure and temperature at this altitude are 0.14 psia and -67 degrees F respectively, Find the volume of hydrogen at 14.7 psia and 60 degrees F that should be added on the ground. Neglect the balloon's weight. THE ANSWER SHOULD BE 6600 ft^3 but I just can't come out with that answer

Finding Pressure

At normal atmospheric conditions, approximately what pressure in MPa must be applied to water to reduce its volume by 3%