Three identical 10 l tanks contain 6 mol of helium (he) at 293 k. the pressure in each of the tanks is increased as described below: tank a: the tank volume is decreased from 10 l to 5 l while the temperature and the number of moles of he remain constant. tank b: the tank temperature is increased from 293 k to 308 k while the volume and the number of moles of he remain constant. tank c: the number of moles of he in the tank is increased from 6 mol to 9 mol while the temperature and the volume remain constant. how is the average kinetic energy, ke, of the he molecules affected in each case?

Which substances have the lowest melting points: ionic covalent, or metallic

The last few miles of the marathon are the most difficult for heather, her hair plastered to her head, sweat clinging to her arms, and her legs already feeling as if they had nothing left, just dead weight. after grabbing a cup of ice water, she feels the ice cubes smash against her nose as she gulps some cool refreshment and keeps on running. in these last few miles, the breeze kicks up and she finally feels some coolness against her skin. drips of sweat, once clinging to her forehead, now spill down, and heather feels more pain as the sweat flows into her eyes. which of the following is the most likely reason why the ice struck heather’s nose when she took a drink? a) water can function as a solvent. b) water can store large amounts of heat. c) water can moderate temperatures through evaporative cooling. d) the density of water decreases when it freezes. e) water has a cohesive nature. sweat remained on heather’s forehead and arms because of the a) high salt content of sweat b) cohesive nature of water c) ability of water to moderate heat d) high evaporative cooling effect of water e) ability of water to act as a solvent

Each of the following reactions is allowed to come to equilibrium and then the volume is changed as indicated. predict the effect (shift right, shift left, or no effect) of the indicated volume change. drag the appropriate items to their respective bins. co(g) + h2o(g) < => co2(g) + h2(g) (volume is decreased) pcl3(g) + cl2(g) < => pcl5(g) (volume is increased) caco3(s)< => cao(s) + co2(g) (volume is increased)