a bottle of copper(II)oxide has been contaminated with solid sodium chloride, how can the sodium chloride be removed?

Copper oxide is totally insoluble in water. The NaCl could therefore be rinsed away.

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To remove the sodium chloride from the bottle of copper(II) oxide, you can follow these steps:

1. Pour some distilled water into the bottle containing the mixture of copper(II) oxide and sodium chloride.
2. Gently shake or stir the mixture to allow the solid sodium chloride to dissolve in the water. This will form a solution.
3. Once the sodium chloride has dissolved, carefully pour the solution into a separate container, leaving behind the insoluble copper(II) oxide.
4. Repeat the process of adding distilled water to the bottle, shaking or stirring, and pouring off the solution until most of the sodium chloride has been removed.
5. Finally, allow the remaining copper(II) oxide to dry, either by leaving it out in open air or using a gentle heat source, such as a drying oven or heat lamp.

By following these steps, you can separate the sodium chloride from the copper(II) oxide.