how could you determine whether all the potassium chlorate had been decomposed after heating it using the law of definite composition?
You know how much oxygen is in the amount KClO3 used in the experiment; measure the oxygen collected to compare.
To determine whether all the potassium chlorate (KClO3) has been decomposed after heating it using the law of definite composition, you would need to compare the mass of the potassium chlorate before and after heating.
Here's how you can do it:
1. Start by accurately measuring the mass of an empty crucible. Record the mass.
2. Add a known quantity of potassium chlorate to the crucible. Measure and record the mass of the crucible with the potassium chlorate.
3. Heat the crucible containing the potassium chlorate using a Bunsen burner or a suitable heating source. The heat decomposes the potassium chlorate into potassium chloride (KCl) and oxygen gas (O2).
4. Continue heating the crucible until all visible signs of decomposition have stopped, indicating that all the potassium chlorate has been decomposed.
5. Allow the crucible to cool down to room temperature. This can be done by removing it from the heat source and leaving it on a heat-resistant surface.
6. Weigh the crucible with the remaining contents (potassium chloride). Record the mass.
7. Compare the mass of the crucible with potassium chlorate before heating (step 2) to the mass of the crucible with potassium chloride after heating (step 6). If all the potassium chlorate has decomposed as per the law of definite composition, the mass of the crucible with the remaining contents should be less than the initial mass of the crucible with the potassium chlorate.
If there's still potassium chlorate residue, the mass of the crucible with potassium chloride after heating will be greater than expected based on the law of definite composition.