Given the following heats of combustion: c2h2(g) = -1300 kj/mole, h2(g) = -286 kj/mole, c2h6(g) = -1560 kj/mole, calculate the enthalpy change for the following reaction
c2h2(g) + 2h2(g) → c2h6(g)
a. -312 kj
b. -26 kj
c. +312 kj
d. -26 kj

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.

Why do scientists look for patterns in the world? a. patterns can explain observations. b. patterns never change, no matter what. c. patterns are easy for scientists to detect. d. patterns are all the same, through all time.

What is the temperature of 0.750 mol of a gas stored in a 6,850 ml cylinder at 2.21 atm? . 2.95 k 5.24 k 138 k 246 k