What method would we use to measure how mass changes during a reaction???

How could a student test the effect of removing heat from a gas that is stored in a sealed container? what must occur in order for matter to change states?

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.

Kp is the equilibrium constant for dissociation of the propionic acid dimer. what is the sign of the slope for a plot of the natural logarithm of kp vs. inverse temperature for this reaction?