Why is the Reaction Rate Directly Proportional to Sulfuric Acid Concentration?

[Positralino]

The reaction I did for the lab is:
H₂SO₄ + Mg --> MgSO₄ + H₂

In my graph, there displays the two variables - the concentration of sulfuric acid and the average rate of reaction in direct proportion. How do I explain the trend?

I know I can explain this qualitatively using collision theory, but to explain why they are in direct proportion requires the rate law from what I know.

Since the graph shows a linear relationship, the experiments show that the order of reaction with respect to sulfuric acid is 1. I think I need to explain this by finding the rate determining step of this reaction and putting the coefficients as the powers, but I do not know the reaction mechanism. Can anyone help me out here and explain why it is this reaction mechanism and which is the rate determining step?

 

[Nino MMP]

The rate law for this reaction is rate = k[H2SO4], which means that the rate of the reaction is directly proportional to the concentration of sulfuric acid. This is because the rate of the reaction is determined by the frequency of collisions between molecules of sulfuric acid and molecules of magnesium, which increases as the concentration of sulfuric acid increases. According to collision theory, the frequency of collisions is proportional to the concentrations of the reactants. Therefore, the rate of reaction increases as the concentration of sulfuric acid increases, resulting in a direct proportion between the concentration of sulfuric acid and the average rate of reaction.