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The molar volume (in units of litres per mole) is the same for all gases at the same temperature and pressure - Scottish Highers Chemistry - Question 10 - 2023
Question 10
The molar volume (in units of litres per mole) is the same for all gases at the same temperature and pressure. Using your knowledge of chemistry, suggest how the mo... show full transcript
Worked Solution & Example Answer:The molar volume (in units of litres per mole) is the same for all gases at the same temperature and pressure - Scottish Highers Chemistry - Question 10 - 2023
Step 1
Suggest how the molar volume of gases could be measured and compared
Answer
To measure and compare the molar volume of gases, one method involves the reaction between a solid and an acid. For instance, we can react zinc with hydrochloric acid in a controlled setup. The gases evolved can be collected using a gas syringe, ensuring accurate volume measurement.
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Setup: Use a gas syringe connected to a delivery tube that leads to the reaction vessel (e.g., 500 cm³ flask).
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Reaction: Add hydrochloric acid to the flask containing zinc, which will release hydrogen gas, displacing the liquid in the gas syringe.
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Data Collection: Measure the volume of hydrogen gas collected after the reaction reaches completion, ensuring that temperature and pressure remain constant for accurate molar volume determination.
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Comparison: Repeat this with different gases, such as by using a vacuum pump with sodium carbonate and water to release carbon dioxide, or using a cylinder of hydrogen directly in the gas syringe. By maintaining the same conditions, the molar volumes can be compared reliably.
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Conclusion: This setup allows for comparison of molar volumes measured at the same temperature and pressure for different gases, thus confirming Avogadro's Principle.