Question 578 of 949
According to Boyle's Law, if the pressure of a gas is doubled while keeping the temperature constant, what happens to the volume of the gas?
- The volume is halved
- The volume is doubled
- The volume remains the same
- The volume is tripled
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 of the gas,
- \( P_2 \) and \( V_2 \) are the final pressure and volume of the gas.
**Scenario Analysis:**
In the scenario given, we are told that the pressure of the gas is doubled while keeping the temperature 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. **Substitute \( P_2 \) with \( 2P_1 \):**
\[
P_1 V_1 = (2P_1) V_2
\]
3. **Divide both sides by \( P_1 \) (assuming \( P_1 \neq 0 \)):**
\[
V_1 = 2 V_2
\]
4. **Rearranging gives us:**
\[
V_2 = \frac{V_1}{2}
\]
This shows that when the pressure is doubled, the volume is halved. Therefore, 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 Boyle's Law, if pressure increases, volume must decrease, not increase.
- **Option C: The volume remains the same**
- This option implies that pressure changes do not affect volume, which is incorrect. Boyle's Law clearly states that pressure and volume are inversely related; thus, a change in pressure will result in a change in volume.
- **Option D: The volume is tripled**
- This option also contradicts Boyle's Law. Tripling the volume would imply a significant decrease in pressure, which is not the case when pressure is doubled.
### 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 Temperature:** Boyle's Law only applies when the temperature is constant. If temperature changes, other gas laws (like Charles's Law) may need to be considered.
- **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 of a gas results in halving its volume.
- The correct answer to the question is A: The volume is halved.
- Remember to always consider the conditions (constant temperature) when applying gas laws.