Stoichiometric Calculations for Magnesium Reaction

Stoichiometric Calculations

Weight of Magnesium Reacted

  • Chemical Reaction:
    • The balanced chemical equation for the reaction of magnesium with oxygen is:
    • [ 2 \text{Mg} + \text{O}_2 \rightarrow 2 \text{MgO} ]

Molar Mass of Reactants

  • Molar Mass Calculations:
    • Magnesium (Mg): 24.3 g/mol
    • Oxygen (O): 16.0 g/mol

Calculation of Magnesium Reacted

  • To find the weight of magnesium that has reacted, consider the molar ratio from the balanced equation:
    • 2 moles of Mg react with 1 mole of O₂ to produce 2 moles of MgO.
    • This indicates that the molar amount of Mg used corresponds directly to the amount of O₂ reacted.

Significant Figures Requirement

  • Significant Figures: Always provide answers in accordance with significant figures.
    • In this problem, based on the given molar mass of magnesium (24.3 g/mol), the answer must reflect the correct significant figures.

Scientific Notation Requirement

  • When presenting the final answer, it should be in scientific notation, specifically E notation.
    • Format: Use 1 digit before the decimal point.
    • Example Format: 2.5e5 (which is equivalent to 2.5 x 10^5).

Example of Calculation (Hypothetical)

  • If 3.0 moles of Mg reacted:
    • Weight of Mg = Number of moles × Molar mass
    • Weight of Mg = 3.0 moles × 24.3 g/mol = 72.9 g
    • In significant figures, this would be presented as 7.29e1 g (as 72.9 has three significant figures, resulting in the format).

Final Answer Presentation

  • The response must be formatted correctly based on the input requirements and show the weight of reacted Mg in scientific notation with the correct significant figures.