Which of the following most likely happens during a physical change? a. an irreversible process takes place. b. substance changes its form but not its molecular composition. c. new atoms are introduced in the molecules of the substance. d. a substance reacts differently with a chemical before and after the change.

What is the typical rotational frequency frot for a molecule like n2 at room temperature (25∘c)? assume that d for this molecule is 1å=10−10m. take the total mass of an n2 molecule to be mn2=4.65×10−26kg. you will need to account for rotations around two axes (not just one) to find the correct frequency. express frot numerically in hertz, to three significant figures.