Chromatography is the only way to separate a mixture of different kinds of molecules .true or fales. why?

This classification of drug typically changes the brain's chemistry and reduces its ability to create its own endorphins.

Agroup of students is studying convection current. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other is in an area with warm air. after 10 minutes, the balloon are released from a height of 1 meter. which of the following to the students most likely observe? a) the warm balloon expands and rises. the cold balloon shrinks and sinks b) the balloon both rise. the cold balloon is larger than the warm balloon c) the cold balloon expands and rises. the warm balloon shrinks and sinks d) the balloon rise at the same rate. both balloons are the same size

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation: