Question 569 of 949
According to Boyle's Law, what happens to the volume of a gas when the pressure is doubled, assuming the temperature remains constant?
- The volume is halved
- The volume is doubled
- The volume remains the same
- The volume increases by a factor of four
Correct Answer:
A
Explanation
**Correct Option: A. The volume is halved**
### Detailed Explanation:
**Understanding Boyle's Law:**
Boyle's Law states that for a given mass of an ideal gas at constant temperature, the pressure (P) of the gas is inversely proportional to its volume (V). This relationship can be mathematically expressed as:
\[ P \propto \frac{1}{V} \]
or, more commonly, in equation form:
\[ P_1 V_1 = P_2 V_2 \]
where:
- \( P_1 \) and \( V_1 \) are the initial pressure and volume,
- \( P_2 \) and \( V_2 \) are the final pressure and volume.
**Scenario Analysis:**
In the question, we are told that the pressure is doubled while the temperature remains constant. Let's denote the initial pressure as \( P_1 \) and the initial volume as \( V_1 \). If the pressure is doubled, we have:
\[ P_2 = 2P_1 \]
Now, we can use Boyle's Law to find the new volume \( V_2 \):
1. **Set up the equation using Boyle's Law:**
\[
P_1 V_1 = P_2 V_2
\]
2. **Substituting \( P_2 \):**
\[
P_1 V_1 = (2P_1) V_2
\]
3. **Dividing both sides by \( P_1 \) (assuming \( P_1 \neq 0 \)):**
\[
V_1 = 2 V_2
\]
4. **Rearranging to find \( V_2 \):**
\[
V_2 = \frac{V_1}{2}
\]
This shows that when the pressure is doubled, the volume is halved. Thus, the correct answer is **A. The volume is halved**.
### Why Other Options Are Incorrect:
- **Option B: The volume is doubled**
- This option suggests that increasing the pressure would lead to an increase in volume, which contradicts Boyle's Law. According to the law, if pressure increases, volume must decrease, not increase.
- **Option C: The volume remains the same**
- This option implies that volume does not change with pressure, which is incorrect. Boyle's Law clearly states that volume and pressure are inversely related; thus, a change in pressure will result in a change in volume.
- **Option D: The volume increases by a factor of four**
- This option suggests a significant increase in volume with an increase in pressure, which is contrary to the principles of Boyle's Law. An increase in pressure leads to a decrease in volume, not an increase.
### Common Pitfalls:
- **Misunderstanding Inverse Relationships:** Students often confuse direct and inverse relationships. Remember that in Boyle's Law, as one quantity increases, the other decreases.
- **Ignoring Constant Temperature:** Boyle's Law applies only when the temperature is constant. If temperature changes, the relationship described by Boyle's Law does not hold.
- **Assuming Ideal Gas Behavior:** Boyle's Law is derived under the assumption of ideal gas behavior. Real gases may deviate from this behavior under high pressure or low temperature.
### Revision Summary:
- Boyle's Law states that pressure and volume of a gas are inversely related at constant temperature.
- Doubling the pressure results in halving the volume.
- The correct answer to the question is A: The volume is halved.
- Remember to consider the conditions (constant temperature) when applying gas laws.