The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder it exists as liquid. When it comes out from the cylinder, it becomes a gas (change - A), then it burns (change - B). The following statements pertain to these changes. Choose the correct one.

Options

A. Process A is a chemical change.
B. Process B is a physical change.
C. Process A is a physical change but B is a chemical change.
D. Process A is a chemical change but B is a physical change.

Answer

To solve the question about the changes that liquefied petroleum gas (LPG) undergoes when used in the kitchen, we need to analyze the two changes described: Change A (the transition from liquid to gas) and Change B (the burning of the gas).

### Step-by-Step Solution:

**Step 1: Identify Change A**
- Change A refers to LPG transitioning from a liquid state to a gaseous state when it exits the cylinder.
- This is a physical change because the state of the substance is changing, but no new substance is formed. The LPG remains LPG, just in a different state.

**Step 2: Identify Change B**
- Change B refers to the burning of LPG.
- This is a chemical change because burning LPG results in the production of new substances, such as carbon dioxide (CO2) and water (H2O), along with the release of heat. In a chemical change, the original substance is transformed into one or more new substances.

**Step 3: Summarize the Changes**
- Change A (liquid to gas) is a physical change.
- Change B (burning) is a chemical change.

**Step 4: Choose the Correct Statement**
- Based on the analysis:
- Option 1: Process A is a chemical change - **Incorrect**
- Option 2: Process B is a physical change - **Incorrect**
- Option 3: Process A is a physical change but B is a chemical change - **Correct**
- Option 4: Process A is a chemical change but B is a physical change - **Incorrect**

Thus, the correct statement is that Change A is a physical change and Change B is a chemical change.

### Final Answer:
The correct option is: **Option 3: Process A is a physical change but B is a chemical change.**

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