Empirical Formula and Magnesium Combustion - Vocabulary

Vocabulary flashcards covering key terms from the notes on empirical formula determination via burning magnesium in air, including related reactions and concepts.

Empirical formula

The simplest whole-number ratio of moles of elements in a compound.

Activation energy

Minimum energy required for a chemical reaction to proceed.

Exothermic reaction

A reaction that releases heat energy.

Magnesium oxide (MgO)

White solid product formed when magnesium burns in oxygen; MgO.

Magnesium nitride (Mg3N2)

Nitride formed when magnesium reacts with nitrogen gas; can be converted to MgO with water.

Magnesium hydroxide (Mg(OH)2)

Intermediate compound formed when Mg reacts with water; decomposes to MgO and H2.

Hydrogen gas (H2)

Gas produced (often flammable) during reactions such as Mg with water.

Oxygen gas (O2)

Gas in the air that reacts with Mg to form MgO.

Nitrogen gas (N2)

Gas in the air that reacts with Mg to form Mg3N2.

Magnesium (Mg)

Elemental metal that burns readily in air.

Carbon dioxide (CO2)

Gas that can react with Mg to form MgO and C; present in reactions in air.

Molar mass

Mass per mole of a substance (g/mol); e.g., Mg = 24.3 g/mol, O = 16.0 g/mol.

Mass percentage

Mass of an element in a compound divided by the compound’s molar mass, times 100%.

Crucible

Heat-resistant dish used to contain and weigh samples during high-temperature experiments.

Combustion

Rapid oxidation producing heat and light; in this context, magnesium burning in air to form MgO.

Molar mass Mg

24.3g

Molar Mass O

16.0 grams

If the combustion had been carried out in pure oxygen, only magnesium oxide would be Produced

2Mg + 02 → 2MgO

Magnesium also reacts with nitrogen gas in the air producing a small amount of magnesium nitride

3Mg + N2 → Mg3N2

2Mg(s) + 02(g)

→ 2 MgO(s) + energy