A student heated a blue copper sulfate crystal in a test tube. After a few minutes, she observed that the crystal turned white and the inside of the test tube was covered with a thin film of water. The water inside the test tube most likely __.Multiple choice question.condensed from the air around the test tubecame from the blue copper sulfate crystal, which is a hydrateseeped through the sides of the test tubewas left from cleaning the test tube the night before
Question
A student heated a blue copper sulfate crystal in a test tube. After a few minutes, she observed that the crystal turned white and the inside of the test tube was covered with a thin film of water. The water inside the test tube most likely __.Multiple choice question.condensed from the air around the test tubecame from the blue copper sulfate crystal, which is a hydrateseeped through the sides of the test tubewas left from cleaning the test tube the night before
Solution
The water inside the test tube most likely came from the blue copper sulfate crystal, which is a hydrate.
Here's why:
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Copper sulfate is a blue crystal in its hydrated form, which means it contains water molecules within its structure. The formula for hydrated copper sulfate is CuSO4.5H2O, indicating it has five water molecules for each unit of copper sulfate.
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When the student heated the crystal, the heat energy provided was enough to break the bonds holding the water molecules within the crystal structure. This process is known as dehydration.
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The water molecules, now free, turned into water vapor due to the heat.
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When this water vapor came into contact with the cooler parts of the test tube, it condensed to form liquid water, creating a thin film of water on the inside of the test tube.
So, the water didn't come from the air around the test tube, seep through the sides of the test tube, or was left from cleaning the test tube the night before. It came from the dehydration of the blue copper sulfate crystal.
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