Theories are used to make predictions true or false

Why does a cake rise when you bake it? ♡

How will the emission of an alpha particle affect the atomic number of an atom

A4.86 g piece of metal was placed in a graduated cylinder containing 15.5 ml of water. the water level rose to 17.3 ml. what is the density of the metal. i need the steps of how to solve it to so i can use a formula to work out other problems.