What happens to the mass of a substance when it is heated, cooled, or mixed with other substances?

The rate constant for the reaction below is 6.2 x 10−5 mol l−1 s −1. if the initial concentration of a is 0.0500 m, what is its concentration after 115 s?

Of element x has 22 protons, how many electrons does it have

Match each state of matter with the statement that best describes it.