At 25 Celsius and 725 Torr pressure, what will be the volume of 0.75 mol of Kr?

Asample of rose gold is: 12.0 g gold, 5.0g silver, and 7.0 g copper. what is the percent copper in the sample?

The name of the ion, s2-, is: sulfurous ion sulfide ion sulfur ion sulfate ion

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?