How do reactant proportions affect the products of a chemical reaction?

Is it correct that if you alter the proportions of the reactants of many chemical reactions, especially step-wise, the products will change? 


Here is an example, please tell me if it is right or not:
\begin{align}
\ce{KOH + H2SO4 &-> KHSO4 + H2O}\\
\ce{2KOH + H2SO4 &-> K2SO4 + 2H2O}
\end{align}




Chemistry is much more complicated than just writing balanced chemical equations. In your case, the reaction is in equilibrium. It would be all much clearer if you took a couple classes of general chemistry.


But if you really want a clear cut answer: since this is an acid-base neutralisation, you would be right. With one equivalent of $\ce{KOH}$, you would find mainly $\ce{KHSO4}$ (with traces of $\ce{KOH}$, $\ce{H2SO4}$ and $\ce{K2SO4}$, which would be mainly dissociated ions anyway.) By adding more, you would shift the equilibrium toward $\ce{K2SO4}$.


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