Severus Snape knows that density of his powder is 3.00 g/cm3 . He also knows he needs 3.00 cm3 of this powder. What mass in grams does he require?

He requires 1 gram of mass.

Explanation:

The density is defined as:

 (1)

Where m is the mass and V is the volume.

Then, m can be isolated from equation 1 in order to determine the mass.

(2)

Hence, he requires 1 gram of mass.

i dont think you are wrong for wanting to get even with someone who did you wrong.

(i'm an eye for an eye kind of person) but if this person hurt you in a sexual way, i dont suggest doing anything to him. he should be taken to the proper authorities, you could go to jail depending on what you do. if it was something small like your sibling took your spot on the couch, than yea, i would get even with him by taking one of his favorite snacks lol. but i dont suggest you doing anything illegal.