Chemistry Practice Test – Symbols, Formulae and Equations (Questions with Answers and Explanations)

The empirical formula of a compound containing 0.067 mol Cu and 0.066 mol O is _____ [Cu = 63.5, O = 16.0]

(a) Cu₂O   (b) CuO    (c) CuO₂  (d) Cu₂O₂

The numerical coefficients in a balanced equation give the ______ 

(a) mass ratio of the reactants
(b) number of molecules and atoms of products only
(c) number of moles of reactants and products
(d) molar mass of the reactants and products.

The molecular formula of a compound expresses the ______ 

(a) ratio of atoms of the different elements in one molecule.
(b) simplest whole number ratio for the atoms of different elements
(c) number of atoms in one molecule of a compound.
(d) number of atoms of the different elements in one molecule.