# Science

## Calculate the unit weight for each layer? and the pressure area and the total stress ?

Calculate the unit weight for each layer? and the pressure area and the total stress ? EXPERT ANSWER

## The Environmental Protection Agency (EPA) wants to restrict the amount of pollutants added by a company to the river water. The concentrations of phenol and nitrogen in the water are to be restricted to, respectively, P and N lbs. MG (million gallons) on a daily basis. The river has a flow of M MG/day. The company diverts a portion of the river water, adds the pollutants, namely, phenol and nitrogen, to it, and sends the water back to the river. The company has four possible ways to treat the water it uses before returning it to the river. The characteristics of each treatment are given in the following table:

The Environmental Protection Agency (EPA) wants to restrict the amount of pollutants added by a company to the river water. The concentrations of phenol and nitrogen in the water are to be restricted to, respectively, P and N lbs. MG (million gallons) on a daily basis. The river has a flow of M MG/day. The …

## 6. A body is dropped from a height of 300ft with an initial velocity of 30 ft /sec. Assuming no air resistance, (a) find an expression for the velocity of the body at any time t; (b) find the time r(1u1red for the body to hit the ground. 7. A ball is propelled straight up with an initial velocity of 250 ft/sec in a vacuum with no air resistance. How high will it go ?

EXPERT ANSWER 6) a) V = U + g*t where U – initial velocity b) h = ut + .5gt^2 300 = 30t + .5* 32.17*t^2 t = 3.49 sec 7) h = u^2 /2g = 250^2/(2*32.17) = 971.4 ft

## Five grams of an organic solid is dissolved in 100 ml of H20 (solvent 1). Which of the following extraction methods will remove the largest amount of the organic solid from the aqueous solution? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a Three 50 ml portion extractions with ether (solvent 2) b Two 50 ml portion extractions with ether (solvent 2) с One 150 ml portion extractions with ether (solvent 2) d One 50 ml portion extractions with ether (solvent 2) o Q.7.2-Post-Lab Caffeine Extraction Homework. Unanswered The pka of 2,5-dinitrophenol is 5.15. Will it dissolve in sodium carbonate solution? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a No, typically organic phenols do not dissolve i aqueous solution b No, because the 2,5-dinitrophenolis basic с Yes, the 2,5-dinitrophenol will react with sodium carbonate, and the resulting salt will dissolve in aqueous solution d Yes, any phenol is soluble in sodium carbonatelution

EXPERT ANSWER Organic extraction Ans: a) Three 50mL extraction with ether (solvent 2). The multiple extraction is effective than the bulk single extraction. Hence Three 50mL would be best. 2,5-Dinitro phenol: Ans: C The 2,5-Dinitrophenol pKa = 5.5, Hence it will react with Sodium bicarbonate (pKa of HCOO– = 6.4, higher than pKa of 2,5-Dinitro phenol) …