Finding the Empirical Formula for Magnesium Oxide part 2.wmv

Experimental Setup

  • Objective: To determine the formula for magnesium oxide by burning magnesium in a controlled environment (porcelain crucible).

  • Equipment:

    • Porcelain crucible and lid

    • Top-loading digital balance (centigram balance)

    • Bunsen burner

    • Crucible tongs

    • Wire triangle for support

Preparing for the Experiment

  • Initial Weighing:

    • Weigh empty crucible with lid: 34.5 g

    • Record this weight for future calculations.

  • Weighing Magnesium:

    • Use crucible tongs to avoid changing weight with fingerprints.

    • Coil magnesium metal ribbon to fit securely at the bottom of the crucible for optimal heating.

Heating Procedure

  • Heating the Crucible:

    • Place crucible in wire triangle to stabilize it above the Bunsen burner.

    • Aim to heat the bottom of the crucible until it glows bright orange.

    • Ensure the hottest part of the Bunsen burner flame is just above the inner blue cone.

  • Introducing Air:

    • Lift the crucible lid briefly to allow oxygen in without losing product.

    • Acknowledge that slight smoke may escape, indicating magnesium oxide formation.

Monitoring Changes

  • Weight Measurements:

    • Conduct multiple weigh-ins after heating and allowing to cool, until weight stabilizes at 34.94 g (crucible + magnesium oxide).

    • Ensure accurate readings by preventing interference from table movements and air currents.

Calculating Data

  • Weight Differences:

    • Calculate the weight of magnesium by subtracting the initial empty crucible weight from the weight after adding magnesium.

    • Use the difference between the final weight (crucible + magnesium oxide) and the initial weight to determine the weight of oxygen absorbed.

  • Empirical Formula Determination:

    • Use weights of magnesium and oxygen to calculate moles of each element involved.

    • From the mole ratio, derive the empirical formula of magnesium oxide (MgO).

Conclusion

  • The experiment allows for the determination of magnesium oxide's formula by careful measurement and observation of the reaction of magnesium with oxygen.

  • Students are encouraged to complete calculations and verify results for the empirical formula of magnesium oxide.