the earth's atmosphere is made up of approximately
__
% nitrogen.
a.1
b.21
c.78
d. none of the above

Which of the following units is not an official si unit? mole liter kilogram ampere

To prevent the presence of air, noble gases are placed over highly reactive chemicals to act as inert "blanketing" gases. a chemical engineer places a mixture of noble gases consisting of 4.37 g of he, 13.36 g of ne, and 36.65 g of kr in a piston-cylinder assembly at stp. calculate the partial pressure in torr of kr.

Concentrations expressed as a percent by mass are useful when the solute is a a. liquid b. gas c. solid