1.A surface water sample has been evaporated until dry in a crucible dish. The dry (tare) weight of the crucible is 44.642gm. The weight of the residue plus the cruciible is 44.6484gm. Determine the total solids (both dissolved and suspended) in the sample if the sample volume was 10 mL.
2.A large concrete channel holds a hydraulic jump in which the subcritical depth of flow is 2.5 m. If 40 percent of the specific energy in the flow is lost through the hydraulic jump, what is the specific discharge in this rectangular channel?
3.An operator is injured when he ismixing up dilute sodium hydroxide solution by adding solid sodiumhydroxide to an open tank containing water. He adds the sodiumhydroxide too fast, and the heat of dilution causes the solution toerupt from the open tank splashing the operator. What is theinherently safest approach to preventing a recurrence of thisincident? a. Buy sodium hydroxide solution from the supplierat the required concentration and eliminate the mixingoperation.
b. Divide the sodium hydroxidecharge into 10 smaller charges, and add them one at a time, makingsure that each is well mixed and the tank temperature has stoppedincreasing before adding the next charge.
c. Reprimand the operator foradding the sodium hydroxide too fast, and hold a meeting to remindall of the other operators to add sodium hydroxideslowly.
d. Design a closed system tocharge solid sodium hydroxide to a closed tank, so the tank isnever open to the work environment.
4.You are going to paint a room inyour house. You have some left over solvent based paint which youcould use. How can you apply inherently safer design philosophy toreduce the risk of painting?
a. Wear impervious gloves when cleaning your paint brushes withsolvent.
b. Open all windows in the roomto provide good ventilation.
c. Handle and store your solventbased paint in an area away from open flames or other potentialignition sources.
d. Contact your local communityhazardous waste disposal facility, take the left over paint tothem, and buy a can of water based paint to paint yourroom.
5.Which process change does notdescribe an application of the inherently safer design strategy“Moderate”?
a. A plant replaces anhydrous ammonia with 20% aqueous ammoniasolution for neutralization of an acidic wastestream.
b. A plant storing anhydrousmonomethylamine (boiling point = -6 degrees C) decides torefrigerate the storage tank to reduce the storage pressure toatmospheric.
c. A process development chemistdiscovers that one of the reactants in a process, sodium hydroxide,reacts in a side reaction with the process solvent ethylenedichloride to form toxic vinyl chloride (listed as a carcinogen bymany regulatory agencies), and replaces the ethylene dichloridewith a non-reactive solvent.
d. A plant which manufacturespolymer paint resins by solution polymerization of acrylic monomersin various organic solvents replaces the dry benzoyl peroxidepolymerization inhibitor with water-wet benzoyl peroxide pastecontaining 25% water, which is more stable.
e. Alfred Nobel invents dynamite,which is made by absorbing nitroglycerine on an inert carrier andis much more stable than pure nitroglycerine.
6.A continuous process tomanufacture methyl isocyanate (the highly toxic material releasedfrom a plant in Bhopal, India in December 1984, resulting inthousands of fatalities) with immediate consumption of the methylisocyanate by downstream processes with a total plant inventory ofa few kilograms is an example of which inherently safer designstrategy?
a. Substitute
b. Minimize
c. Simplify
d. Moderate