Write any two substances or solid which charge by this process

Which of the following is considered to be a vector?               a.  temperature    b.  velocity    c.  time    d.  mass

The first law of thermodynamics states that heat added to a system is neither created nor destroyed but is transformed ⇒ as it changes into other forms of energy.

Look at the potential energy diagram for a chemical reaction. which statement correctly describes the energy changes that occur in the forward reaction?