Question

#2 (a), (b), (c), (d)

2. Consider the chemical equation for the synthesis of magnesium oxide, from its elements: 2 MgO(s) +O2(B) 2 Mg(s) What is the simplest ratio of particles of reactants and products? a) How many molecules of oxygen are needed to react with 100 atoms of magnesium? b) How many molecules of magnesium oxide are produced if 10 atoms of magnesium reacts with c) sufficient oxygen? How many molecules of oxygen are needed produce 50 molecules of magnesium oxide? d)

Answer 1

2Mg + O2 ----> 2MgO

A)

Simplest mole ratio; ( stoichiometric coefficients)

Mg : O2 : MgO = 2 : 1 : 3

B)

Moles of Mg = atoms/Avogadro number = 100 / 6.023*10^23 = 16.603*10^-23 moles

Thus moles of O2 = 16.603*10^-23 / 2 = 8.302*10^-23 moles of O2

Molecules of O2 = 8.302*10^-23 * 6.023 * 10^23 = 50 molecules ....Answer

C) As per stoichiometry of reaction

Molecules of MgO = atoms of Mg = 10 ...Answer

D)

Molecules of O2 = 50/2 = 25 molecules