Item SB005001: If the number of atoms in the sealed jar stayed the same, the mass of the jar and everything inside it will stay the same because the mass of the atoms inside the jar stayed the same.

A student placed a liquid in a jar and sealed it. Then she heated the liquid and it turned into a gas. If the number of atoms in the sealed jar stayed the same, what happened to the mass of the jar and everything inside it after she heated it?

  1. The mass increased because the mass of the atoms inside the jar increased.
  2. The mass decreased because the mass of the atoms inside the jar decreased.
  3. The mass stayed the same because the mass of the atoms inside the jar stayed the same.
  4. Whether the mass increased, decreased, or stayed the same depends on whether a chemical reaction occurred.