Share
Explore BrainMass

Molecular Engineering

Molecular engineering studies molecules that are used to create new molecules which may not exist in nature. This process is difficult requiring manual manipulation of molecules using such devices as a scanning tunneling microscope. It is expected that eventually to exploit lifelike self-replication ‘helper molecules’ that are themselves engineered. Therefore, the field can be seen as a precision form of chemical engineering.

Molecular engineering is an important aspect of pharmaceutical research and materials science. The advent of the scanning tunneling microscope and picosecond-burst lasers in the 1990s, plus discovery of new carbon nanotube applications to motivate mass production of these custom molecules which drove the field forward to commercial reality in the 2000s. Future developments in molecular engineering hold out the promise of great benefits, as well as risks. Nanotechnology discussions spark more controversy in the fields of science and engineering.

Mixture of Perfect Gases

A mixture of perfect gases consist of 3kg of carbon monoxide and 1.5kg of nitrogen at a pressure of 0.1 MPa and a temperature of 298.15 K. Using table 5-1, find: a) the effective molecular mass of the mixture b) its gas constant c) specific heat ratio d) partial pressures e) density Please see the attachment for a comple

Continuous Stirred Tank Reactor (CSTR):Flow rate and Reactor Volume

The liquid phase reactions a. A+B--->C b. A+B--->D are carried out in a perfectly insulated CSTR. The desired reaction (a) is first order in A and zero order in B, while the undesired reaction (b) is zero order in A and first order in B. The feed rate is equimolar in A and B. Species A enters the reactor at a temperatu

Material balances for combustion of octane

One of the most common chemical reactors found around us is the car engine. It takes gasoline and reacts it with air to release chemical energy, which in turn is transformed into mechanical energy. Emissions from your car's engine have been an environmental concern for many years. Using the concepts of material balances,

BOD of Algae

Large blooms of algae result from high nutrient loading in rivers and lakes, for example, as a result of runoff of fertilizers from agricultural fields. When the algae die, they biodegrade and consume oxygen. The amount of oxygen consumed is called the biochemical oxygen demand (BOD). If the level of oxygen dissolved in water be

Mass and Energy Transfer

If we approximate the atmosphere to be 79% nitrogen (N_2) by volume and 21% oxygen (O_2), estimate the density of air (kg/m^3) at STP conditions (0 degrees C, 1 atm)

Gas Absorption and Transfer Operations: Column Diameter Calculation

A gas absorption column to handle 3630 kg/hr of a gas is being designed. Based on pressure drop, entrainment and foaming considerations, the maximum vapor velocity must not exceed 0.61 meters/sec. If the density of the vapor is 0.801 kg/m^3, what is the column diameter?

If a 22450lb (total gross weight) airplane develops 8160lbf thrust...

1) If a 22450lb (total gross weight) airplane develops 8160lbf thrust from each of its two engines and has a wing area of 312ft2 and wing-span of 53.5ft. And a empty weight of 11770lbf. Determine the thrust to weight ratio and the wing loading of this aircraft? 2) Consider an ordinary, helium-filled party balloon with a volu

Combustion Reactions- Thermochemistry

1. A constant-volume tank consists of a mixture of 120 grams of methane (CH4) gas and 600 grams of O2 at 25 degrees C and 200 kPa. The contents of the tank are now ignited, and the methane gas burns completely. If the final temperature is 1200K, determine (a) the final pressure in the tank, (b) the dry analysis of the product st

Combustion of Ethane: Stack Gas Molar Composition

Ethane is burned with 50% excess air. The percentage conversion of ethane is 90%. Of the ethane burned, 25% reacts to form CO and the balance reacts to form carbon dioxide. Calculate the molar composition of the stack gas on a dry basis, and the mole ratio of water to dry stack gas.

Kinetics from CSTR Data

Problem. The kinetics of an aqueous phase decomposition of A is investigated in two CSTR's in series, the first having half the volume of the second. At steady state with a feed concentration of 4 gmol/lit., and mean residence time of 65 sec in the second reactor, the concentration of feed to second from the first is found to b

Distillation and Reflux: Ponchon-Savarit Method

1000 kg/hr of a mixture containing 42 mole percent heptane and 58 mole percent ethyl benzene is to be fractionated to a distillate containing 97 mole percent heptane and a residue containing 99 mole percent ethyl benzene using a total condenser and feed at its saturated liquid condition. The enthalpy-concentration data for the h

Number of Plates at Total Reflux

Problem: A mixture of benzene and toluene containing 40 mole % of benzene is to be separated to give a product of 90 mole % of benzene at the top and bottom product with not more than 10 mole % of benzene. Using an average value of 2.4 for the volatility of benzene relative to toluene, calculate the number of theoretical plates

Differential Distillation Benzene and Toluene Separation: Rayleigh's Equation

Please see the attached file for the fully formatted problem(s). 100 moles of Benzene (A) and Toluene mixture containing 50% (mole) of Benzene is subjected to a differential distillation at atmospheric pressure till the composition of benzene in the residue is 33%. Calculate the total moles of the mixture distilled. Average

Equilibrium Flash Distillation

A feed of 50 mole % hexane and 50 mole % octane is fed into a pipe still through a pressure reducing valve and then into a flash disengaging chamber. The vapor and liquid leaving the chamber are assumed to be in equilibrium. If the fraction of the feed converted to the vapor is 0.5, find the compositions of the top and bottom pr

McCabe-Thiele Method: Calculation of Theoretical Plates

The solution is detailed and well presented. Problem: A saturated liquid mixture containing 60 mole % benzene and 40 mole % toluene is to be distilled continuously into a distillate product containing 90 mole % benzene and the bottom product containing 5 mole % benzene. The fractional distillation column will operate at ap