Which observation most likely indicates that only a chemical change has taken place? the change cannot be reversed.
the shape changes.
states of matter changes.
a reaction occurs.

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

Can someone me with 3 and 4 plz. this is for masteries test.

Each of the following reactions is allowed to come to equilibrium and then the volume is changed as indicated. predict the effect (shift right, shift left, or no effect) of the indicated volume change. drag the appropriate items to their respective bins.co(g) + h2o(g) < => co2(g) + h2(g) (volume is decreased) pcl3(g) + cl2(g) < => pcl5(g) (volume is increased) caco3(s)< => cao(s) + co2(g) (volume is increased)