3.14. Limestone (calcium carbonate) particles are stored in 50-L bags. The void fraction of the particulate matter is 0.30 (liter of void space per liter of total volume) and the specific gravity of solid calcium carbonate is 2.93 (a) Estimate the bulk density of the bag contents (kg CaCO3liter of total volume). (b) Estimate the weight (W) of the filled bags. State what you are neglecting in your estimate. (c) The contents of three bags are fed to a ball mill, a device something like a rotating clothes dryer containing steel balls. The tumbling action of the balls crushes the limestone particles and turns them into a powder. (See pp. 21-64 of Perry's Chemical Engineers' Handbook, 8th ed.) The limestone coming out of the mill is put back into 50-L bags. Would the limestone (i) just fl three bags, (i) fall short of filling three bags, or (ii) fill more than three bags? Briefly explain your answer.

20 standard cubic meters of HCN is released into a 20 meter tubed space. Windless vertical diffusion is                     E ≈ 5x104 cm2 s-1   The density of HCN in the gas form is 0.000761 g/cm3.  At 100 meters away from the release point, what is the time required for HCN to rise to dangerous levels ~100 mg/m3? What if an air conditioner in the 20 meter tubed space is moving air at 0.3 m/s?

Spherical, microporous silica particles used in chromatography have a density of 2.20 g/mL, a diameter of 10.0 mm, and a measured surface area of 300 m2/g. (a) The volume of a spherical particle is 43 pr3, where r is the radius. The mass of the sphere is volume X density (= mL X g/mL). How many particles are in 1.00 g of silica? (b) The surface area of a sphere is 4pr2. Calculate the surface area of 1.00 g of solid, spherical silica particles. (c) By comparing the calculated and measured surface areas, what can you say about the porosity of the particles?

A rectangular fin 1.0 ft long, 1.0 ft wide, and 2in. thick loses heat to the atmosphere at70 F. The base of the fin is at 270 F.If h = 2Btu/h*ft2* F and the thermal conductivity of the fin is 24Btu/h*ft* F, find:(a) The fin efficiency.(b) The total rate of heat loss from the fin.Ans. (a) 70.5%. (b) 712 Btu/h.