Describe the freedom of movement of particles as a substance changes states of matter from solid to liquid to gas.

in a sold the particles are in a fixed position and can only vibrate on the spot but when it changes into a liquid the energy is used to weaken the bonds so there are weak forces of attraction between the particles, all particles are still touching each other but are now free to move around. Ina gas all the bonds are broken, the gas particles are free to move around anywhere and the more collisions there are, the more the pressure increases

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.