Switchgrass is used for ethanol production. The composition of the switchgrass is 37% cellulose, 24% xylan, 3% galactan, 4% arabinan, 20% lignin, 7% extractives, and 5% ash. A dilute acid pretreatment method is applied to the switchgrass before enzymatic hydrolysis and fermentation. The pretreatment hydrolyzes 10% hexosan and 90% pentosan into monomeric sugars. Approximately 30% of the hydrolyzed pentoses are decomposed to furfural. Assume that there is no decomposition of the hydrolyzed hexoses. Assume that lignin, extractives, and ash do not change during the pretreatment. Required:
How much sugars (glucose, xylose, galactose, and arabinose, respectively) are produced when pretreating 1,000 kg (dry matter) switchgrass?

Hot air balloons float in the air because of the difference in density between cold and hot air. in this problem, you will estimate the minimum temperature the gas inside the balloon needs to be, for it to take off. to do this, use the following variables and make these assumptions: the combined weight of the pilot basket together with that of the balloon fabric and other equipment is w. the volume of the hot air inside the balloon when it is inflated is v. the absolute temperature of the hot air at the bottom of the balloon is th (where th> tc). the absolute temperature of the cold air outside the balloon is tc and its density is ďc. the balloon is open at the bottom, so that the pressure inside and outside the balloon is the same. as always, treat air as an ideal gas. use g for the magnitude of the acceleration due to gravity.

Match term definition ellipse a) diagonal cross section of a cylinder circle b) diagonal cross section through the widest part of a sphere sphere c) cross section parallel to the base of a cone great circle d) shape created when a semi-circle is rotated around the y-axis triangle e) perpendicular cross section of a cone

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)