In the Sl system of units, the mole is one of seven base units. It is frequently used in chemical calculations. However, a mole of something is just a particular quantity
of it. It is not a unit of measure in the way that meters, seconds, and kilograms are.
Calculations performed with the number of moles of a substance could also be
performed with the number of particles of a substance. Based on this information,
do you think that the mole should be considered a base unit in the Sl system?
Explain why or why not.

How has the scientific community addressed the safety of chemicals? a. chemicals are repeatedly tested, even those that have existed for a long time. b. existing chemicals are tested if they have never been tested before. c. chemicals are tested if they are suspected to have caused a problem. d. only new chemicals are tested.

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

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.