[Al2CO3]

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:

KOH + H2SO4  KHSO4 + H2O

2KOH + H2SO4  K2SO4 + 2H2O

[Al2CO3]

How does changing the amounts of reactants in a chemical reaction change the chemical compositions of the products?

[sjb]

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:

KOH + H₂SO₄  KHSO₄ + H₂O

2KOH + H₂SO₄  K₂SO₄ + 2H₂O

Quite possibly - look into kinetics and thermodynamics of reactions. It is also possible that two moles of base and two of acid may give one of double salt and one non-reacted acid, rather than 2 moles of mono salt - or any mixture in between, depending on conditions.

[Kaspijs]

[EDIT] got the question wrong, sorry

[Arkcon]

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:

KOH + H2SO4  KHSO4 + H2O

2KOH + H2SO4  K2SO4 + 2H2O

Yes.  That's one way the sodium salt is made: https://en.wikipedia.org/wiki/Sodium_bisulfate#Production  Although its also made by another method.  The final product will depend on how much KOH you have in solution.