Environmental Engineering Chapter 1 Homework The integrated form of the mass balance equation is

1.1-1.7 The solutions for these problems are the solutions for problems 1.1-1.7 in the 2nd

1.8 The washing machine is a batch reactor in which a first order decay of grease on the

clothes is occurring. The integrated form of the mass balance equation is:

Next, calculate the grease remaining on the clothes after 5 minutes:

Q0, C0Qs, Cs

Qb, C0

farm

Plateau Creek

C.V.

Qf/2, Cf

1.9

Qf, C0

a. A mass balance around control volume (C.V.) at the downstream junction

yields

b. Noting that Qb = Q0 – Qf and Qs = Q0 – Qf/2 the mass balance becomes

1.10 Write a mass balance on a second order reaction in a batch reactor:

Accumulation = Reaction

1.11-1.13 The solutions for these problems are the solutions for problems 1.8-1.10 in the

2nd edition Solutions Manual.

1.14 Calculate the pipe volume, Vr, and the first-order rate constant, k.

1.15 The stomach acts like a CSTR reactor in which a first order decay reaction is

occurring.

1.16-1.20 The solutions for these problems are the solutions for problems 1.11-1.15

in the 2nd edition Solutions Manual.

1.21 a. Calculate the volume that 1 mole of an ideal gas occupies at 1 atm and 20 °C.

b. Draw a sketch of the valley as the CSTR, non-steady state control volume.

c. The mass balance for the CSTR control volume is

1.22 a.

b. The reaction (P1.3) is second-order (see the rate constant’s units) so that

1.23 – 1.37 The solutions for these problems are the solutions for problems 1.16-1.30 in

the 2nd edition Solutions Manual.