Why does increasing concentration generally increase the rate of a reaction?

For the reaction C(s, diamond) → C(s, graphite), ∆G = -0.693 kcal/mol (-2.90 kJ/mol) at 25 °C.If a catalyst changes the activation energy of a forward reaction from 28.0 kcal/mol to 23.0 kcal/mol, what effect does it have on the reverse reaction?

a. What is meant by the rate of a reaction?

How would each of the following change the rate of the reaction shown here?2SO₂(g) + O₂(g) → 2SO₃(g)a. adding some SO₂(g)

How would each of the following change the rate of the reaction shown here?2NO(g) + 2H₂(g) → N₂(g) + 2H₂O(g)c. removing some H₂(g)

For the reaction C(s, diamond) → C(s, graphite), ∆G = -0.693 kcal/mol (-2.90 kJ/mol) at 25 °C.If a catalyst changes the activation energy of a forward reaction from 28.0 kcal/mol to 23.0 kcal/mol, what effect does it have on the reverse reaction?