Practical: Determine the Formula of a Metal Oxide
2 guided lessons · 18 checks · 1. Principles of Chemistry → Chemical Formulae, Equations, Calculations
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Determine the Formula of Magnesium Oxide
Magnesium ribbon burns in air inside a crucible, and the ribbon gains every gram of oxygen it bonds with. Weigh the crucible before and after, subtract carefully, and the masses of magnesium and oxygen fall out. Divide each by its relative atomic mass and the mole ratio writes the empirical formula.
What you know already
The previous note showed how a formula falls out of mass measurements taken before and after a reaction. This note runs that method twice at the bench: burning magnesium in air to catch the oxygen it gains, and stripping oxygen back out of copper oxide with methane, then converting both sets of masses into the mole ratio that writes the formula.
Key points of understanding
- The aim is the empirical formula of magnesium oxide, determined by combustion of magnesium in a crucible.
- Weigh the crucible with its lid first, then again with the magnesium inside, and subtract for the metal's mass.
- Lift the lid frequently: enough air enters for full oxidation, but magnesium oxide smoke must not escape.
- Keep heating until the mass stays constant - the maximum mass shows the reaction is complete.
- Divide each mass by its relative atomic mass, simplify the mole ratio, and write it as MxOy, for example MgO.
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1.Determine the Formula of Magnesium Oxide
Magnesium ribbon burns in air inside a crucible, and the ribbon gains every gram of oxygen it bonds with. Weigh the crucible before and after, subtract carefully, and the masses of magnesium and oxygen fall out. Divide each by its relative atomic mass and the mole ratio writes the empirical formula.
Key points
- The aim is the empirical formula of magnesium oxide, determined by combustion of magnesium in a crucible.
Guided content from the SME authoring corpus — note rn_yj4y972FxCWnDnSg, pinned at da18433ed9e8 · promoted SyllabAI/syllabai-resources e967e75f1339
