BL Ch 3 Chem Reactions and Stoich

Antoine Lavoisier

Isaac Newton

Dmitri Mendeleev

Marie Curie

To represent chemical reactions concisely

To describe physical changes

To list all elements in a compound

To show the color of chemicals

Gas state

Solid state

Liquid state

Aqueous solution

Coefficients are used to balance the equation.

Changing subscripts changes the identity of the compound.

Reactants are always on the right side of the equation.

The law of conservation of mass must be followed.

Combination reactions

Decomposition reactions

Combustion reactions

Displacement reactions

They are generally rapid reactions that produce a flame.

They usually involve oxygen as a reactant.

They always produce carbon dioxide and water.

They can occur without oxygen.

2 Mg(s) + O2(g) → 2 MgO(s)

CaCO3(s) → CaO(s) + CO2(g)

CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)

2 KClO3(s) → 2 KCl(s) + O2(g)

Because ionic compounds exist as a three-dimensional order of ions and not as discrete molecules.

Because ionic compounds are always gases at room temperature.

Because ionic compounds are made only of metals.

Because ionic compounds have variable compositions.

The percent composition of an element in a compound.

The molar mass of a compound.

The number of moles in a sample.

The empirical formula of a compound.

The molar mass of a substance is the mass of 1 mole of that substance.

For diatomic elements, the molar mass is twice the atomic weight.

The formula weight in amu is numerically equal to the molar mass in g/mol.

Molar mass is only used for ionic compounds.

One mole of molecules contains Avogadro's number of molecules, and one mole of formula units contains Avogadro's number times the number of atoms or ions in the compound.

One mole of molecules contains twice Avogadro's number of molecules.

One mole of formula units contains half Avogadro's number of atoms.

One mole of atoms contains Avogadro's number times the number of molecules.