State whether the following statements are true or false: Liquefaction of air is a chemical change.

Answer

To determine whether the statement "Liquefaction of air is a chemical change" is true or false, we can analyze the process step by step.

### Step 1: Understand the Process of Liquefaction
Liquefaction of air refers to the process of converting air (a gas) into liquid form. This is typically achieved by applying high pressure and lowering the temperature.

**Hint:** Think about what happens to gases when pressure is applied.

### Step 2: Identify the Nature of the Change
When air is liquefied, it undergoes a change in state from gas to liquid. This is a physical change because it involves a change in the state of matter without altering the chemical composition of the substances involved.

**Hint:** Consider whether any new substances are formed during the process.

### Step 3: Determine if a New Substance is Formed
In the liquefaction of air, no new substances are created. The components of air (like nitrogen, oxygen, and other gases) remain the same; they are simply in a different physical state (liquid instead of gas).

**Hint:** Ask yourself if the original materials can be recovered unchanged after the process.

### Step 4: Classify the Change
Since no new substances are formed and only the state of the air changes, this process is classified as a physical change, not a chemical change.

**Hint:** Remember the definitions of physical and chemical changes.

### Conclusion
Based on the analysis, the statement "Liquefaction of air is a chemical change" is **false**.

**Final Answer:** False

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