Quantitative Chemistry: Conservation of Mass and Reactions

Conservation of mass

Mass of reactants equals mass of products.

Limiting reactant

Reactant that is completely consumed first.

Excess reactant

Reactant that remains after the reaction.

Moles

Amount of substance measured in grams per mole.

Avogadro constant

6.022 x 10²³ particles per mole.

Relative atomic mass

Mass of an atom compared to carbon-12.

Relative formula mass (Mr)

Sum of relative atomic masses in a formula.

Concentration

Amount of solute per volume of solution.

Theoretical yield

Maximum expected mass of product from reaction.

Percentage yield

Actual yield divided by theoretical yield, times 100.

Atom economy

Proportion of atoms in useful products.

Moles of gas

One mole occupies 24 dm³ at RTP.

Titration

Technique to determine concentration of unknown solution.

Burette

Device for delivering precise volumes of liquid.

Titre

Volume of titrant used in titration.

Concordant titres

Repeated titrations within 0.1 cm³ of each other.

Mass concentration

Concentration measured in grams per dm³.

Balanced equation

Equation with equal number of each atom.

Chemical reaction

Process where reactants transform into products.

Gas production

Mass decrease when gas escapes during reaction.

Mass increase

Mass increase when gas is a reactant.

Volume conversion

1 dm³ equals 1000 cm³.

Sodium carbonate decomposition

Produces sodium oxide and carbon dioxide gas.

Magnesium oxidation

Combines with oxygen to form magnesium oxide.

Indicator

Substance that changes color at endpoint of titration.