AP Chemistry Outline 
Chapter 3 – Calculations with Chemical Formulas and Equations 
Antoine Lavoisier – He observed that the total mass of all substances present after a 
chemical reactions is the same as the total mass before the reaction. This is known as the 
law of conservation of mass. 
With Lavoisier’s law, chemists may now make the inference that Atoms are neither 
created nor destroyed during any chemical reaction. 
Stoichiometry – The quantitative nature of chemical formulas and chemical reactions 
All Alkali metals react with water to form their hydroxide compounds and hydrogen gas. 
2K + 2H2O ? 2KOH + H2 
2Na + 2H2O ? 2NaOH + H2 
Combustion reactions are rapid reactions that produce a flame. Oxygen gas is a required 
reactant in order for combustion to occur. When hydrocarbons react with oxygen gas, 
they form CO2 and H2O. HOWEVER, when there is an insufficient quantity of O2, 
carbon monoxide is formed. Even more severe restriction of O2 will cause the production 
of fine particles called soot. 
C3H8 + 5O2 ? 3CO2 + 4H2O 
Combination reactions occur when two or more substances react to form one product. 
Also known as synthesis. Magnesium burning with oxygen to from magnesium oxide is 
an example. 
2Mg + O2 ? 2MgO 
When a combination reactions occurs between a metal and a nonmetal, the product is an 
ionic solid. 
In a decomposition reaction, one substance undergoes a reaction to produce two or more 
substances. Metal carbonates decompose to form metal oxides and carbon dioxide when 
CaCO3 ? CaO + CO2