Question 10 of 949
A gas at a volume of V0 in a container at pressure P0 is compressed to one-fifth of its volume. What will be its pressure if the magnitude of its original temperature T is constant?
- A. P0/5
- B. 4P0/5
- C. P0
- D. 5P0
Correct Answer:
D
Explanation
The correct option for the question is **D. 5P0**.
### Step-by-Step Explanation
1. **Understanding the Problem**:
- We have a gas in a container with an initial volume \( V_0 \) and an initial pressure \( P_0 \).
- The gas is compressed to one-fifth of its original volume, which means the new volume \( V \) is \( \frac{V_0}{5} \).
- The temperature \( T \) of the gas remains constant throughout this process.
2. **Applying Boyle's Law**:
- Since the temperature is constant, we can use Boyle's Law, which states that for a given mass of gas at constant temperature, the product of pressure and volume is constant. Mathematically, this is expressed as:
\[
P_1 V_1 = P_2 V_2
\]
- Here, \( P_1 \) and \( V_1 \) are the initial pressure and volume, and \( P_2 \) and \( V_2 \) are the final pressure and volume.
3. **Substituting Known Values**:
- We know:
- \( P_1 = P_0 \)
- \( V_1 = V_0 \)
- \( V_2 = \frac{V_0}{5} \)
- Plugging these values into Boyle's Law gives:
\[
P_0 \cdot V_0 = P_2 \cdot \frac{V_0}{5}
\]
4. **Solving for Final Pressure \( P_2 \)**:
- Rearranging the equation to solve for \( P_2 \):
\[
P_2 = \frac{P_0 \cdot V_0}{\frac{V_0}{5}} = P_0 \cdot 5
\]
- Thus, we find:
\[
P_2 = 5P_0
\]
5. **Conclusion**:
- The final pressure of the gas after it has been compressed to one-fifth of its original volume, while keeping the temperature constant, is \( 5P_0 \).
### Why Other Options Are Incorrect
- **Option A: \( \frac{P_0}{5} \)**:
- This option suggests that the pressure decreases significantly. However, since the volume is reduced, the pressure must increase, not decrease.
- **Option B: \( \frac{4P_0}{5} \)**:
- This option also implies a decrease in pressure. The relationship defined by Boyle's Law indicates that pressure increases as volume decreases when temperature is constant.
- **Option C: \( P_0 \)**:
- This option suggests that the pressure remains the same. However, since the volume is reduced to one-fifth, the pressure must increase significantly, as shown in our calculations.
### Common Pitfalls
- **Ignoring Temperature**: It's crucial to remember that Boyle's Law applies only when the temperature is constant. If the temperature were to change, we would need to consider the ideal gas law instead.
- **Misunderstanding Volume Change**: Some students may confuse the relationship between volume and pressure, thinking that a decrease in volume would lead to a decrease in pressure, which is incorrect.
### Revision Summary
- Boyle's Law states that \( P_1 V_1 = P_2 V_2 \) for a gas at constant temperature.
- When a gas is compressed to one-fifth of its volume, its pressure increases by a factor of five.
- The final pressure is calculated as \( P_2 = 5P_0 \).
- Always ensure to keep track of temperature conditions when applying gas laws.