How many moles of magnesium is 6.02 x 1022 atoms of magnesium?

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 tendency of water molecules to stick together is referred to as a) adhesion b) polarity c) cohesion d) transpiration e) evaporation

Sum of brother and sisters age is 26. four times the brothers age is subtracted from three times the sisters age, the difference is 8. what are the ages of the brother and sister?