Any factor that causes molecules to collide more frequently speeds up the reaction rate. This is achieved by an increase of the reactants concentration, surface area, raised temp. , raised pressure of gaseous reactant, or an addition of catalysts to the reactant
<u>Answer:</u>
<em>B. A and B</em>
<em></em>
<u>Explanation:</u>
1. Solids have a definite volume, definite size and definite shape
2. The particles present in a solid are very closely packed since the intermolecular forces between them are very strong. The molecules do not move apart.
3. Melting point is the temperature at which solid changes into a liquid.
4. When a solid is heated to the melting point the intermolecular forces are overcome by the energy and the molecules present in it moves from its fixed position to take its liquid state which is called as melting.
<span>They have chloroplasts and use light energy to make more food. I think might be wrong </span>
With a physical change you can actually see it change like ice turning into water, then with a chemical change you can't see it change, although within the molecules themselves they change which makes that possible.
Hope this helps!
