Exercise - STOICHIOMETRY

1. The reactant which is consumed earlier and gives least quantity of product is called;

• a) Reactant in excess
• b) Stoichiometry
• c) Limiting reactant
• d) Stoichiometric amount

vi. Which one of the following compounds contains the highest percentage by mass of nitrogen?

• a) ${\mathrm{N}\mathrm{H}}_3$$\mathrm{NH}_{3}$
• b) ${\mathrm{N}}_2{\mathrm{H}}_4$$\mathrm{N}_{2}\mathrm{H}_{4}$
• c) NO
• d) ${\mathrm{N}\mathrm{H}}_4\mathrm{O}\mathrm{H}$$\mathrm{NH}_{4}\mathrm{OH}$

vii. Vitamin A has a molecular formula of ${\mathrm{C}}_{20}{\mathrm{H}}_{30}\mathrm{O}$$\mathrm{C}_{20}\mathrm{H}_{30}\mathrm{O}$ . The number of moles of vitamin A in 500 mg of its capsule will be;

• a) 1.7
• b) $1.7\times {10}^{-3}$$1.7\times 10^{-3}$
• c) 1.05
• d) $3.01\times {10}^{-3}$$3.01\times 10^{-3}$

viii. When one mole of each of the following is completely burnt in oxygen, which will give the largest mass of ${\mathrm{C}\mathrm{O}}_2$$\mathrm{CO}_{2}$ ?

• a) Carbon monoxide
• b) Diamond
• c) Ethane
• d) Methane

ix. One mole of ethanol and one mole of ethane have an equal;

• a)Mass
• b)Number of atoms
• c)Number of electrons
• d)Number of molecules

x. How many moles of oxygen are needed for the complete combustion of two moles of butane, ${\mathrm{C}}_4{\mathrm{H}}_{10}$$\mathrm{C}_{4}\mathrm{H}_{10}$ ? $2{\mathrm{C}}_4{\mathrm{H}}_{10(g)}+13{\mathrm{O}}_{2(g)}⟶8{\mathrm{C}\mathrm{O}}_{2(g)}+10{\mathrm{H}}_2{\mathrm{O}}_{(l)}$$2\mathrm{C}_{4}\mathrm{H}_{10(g)} + 13\mathrm{O}_{2(g)}\longrightarrow 8\mathrm{CO}_{2(g)} + 10\mathrm{H}_{2}\mathrm{O}_{(l)}$

• a) 12 mol
• b) 13 mol
• c) 4 mol
• d) 10 mol