Which of the following most likely indicates that a chemical change has
happened?

a. an icicle melts in the sun
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b. there's a loud sound when a jet airplane starts its engines.

c. a can is crushed when it is stepped on.

d. a plate breaks when it falls to the floor.

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.