PAG 1.2 Determination of Relative Atomic Mass of Magnesium Latest Update Graded A+

PAG 1.2 Determination of Relative Atomic Mass of Magnesium Latest Update Graded A+ **What errors occur when Mg is added to the experiment, affecting the calculated relative atomic mass of Mg? ** - **Smaller volume error:** This occurs because some gas escapes before the bung (stopper) is replaced on the reaction flask. This escaping gas is not measured and thus leads to a smaller recorded volume of gas. - **Larger volume error:** When the bung is replaced on the reaction flask, it displaces an equivalent volume of air into the measuring cylinder. This displaced air is counted as part of the gas volume, leading to an artificially larger volume reading. **Explanation:** These errors affect the accuracy of the measured gas volume, which is directly used to calculate the amount of Mg reacted and hence its relative atomic mass. The smaller volume error underestimates the amount of gas produced, while the larger volume error overestimates it, both resulting in inaccurate relative atomic mass calculations. **How would you modify this experiment to minimize errors in the measured volume of gas when mixing Mg and acid? ** - **Modification:** Suspend the magnesium above the acid using cotton so that it drops into the acid immediately upon replacing the bung. This eliminates the time lag between adding Mg and sealing the flask, reducing the loss of gas due to escape before sealing. **Explanation:** By ensuring immediate contact between Mg and acid upon sealing, the setup minimizes the delay during which gas could escape, thus improving the accuracy of gas volume measurements and subsequent calculations. **Considering room temperature and pressure were assumed, outline a plan to measure actual temperature and pressure, and apply the ideal gas equation for accurate analysis. ** - **Plan:** Measure the gas volume using a suitable apparatus. Record the actual temperature and pressure during the experiment. Apply the ideal gas equation ( n = frac{PV}{RT} ) to calculate the number of moles of gas produced. **Explanation:** Room conditions vary, impacting gas properties. Measuring temperature and pressure allows correction to standard conditions (STP), enhancing accuracy. The ideal gas equation accounts for gas deviations from STP, vital for precise Mg atomic mass calculations. **What hazards are associated with purifying magnesium sulfate synthesized for determining its relative atomic mass? ** - **Hazards:** During water evaporation, sulfuric acid (H2SO4) also evaporates. Inhalation or contact with acid vapor or residue can cause irritation or burns. Adequate ventilation and personal protective equipment (PPE) are essential during this process. **Explanation:** Handling concentrated acids involves risks due to their corrosive nature. Water evaporation releases acid vapors, posing inhalation risks. Proper ventilation and PPE safeguard against acid exposure, ensuring