How many atoms are in 123 g of calcium

Once similarity and one difference between a mixture of elements and a mixture of compounds

If 22.5 of nitrogen at 748 mm hg are compressed to 725 mm hg at constant temperature. what is the new volume?

The velocity of any object depends upon a) the location of the object. b) the location of the observer. c) which measurement tools are used. d) the relative motion of the observer.