If 1 L of gas A at 600 torr and 500 mL of gas B at 1000 torr are placed in 2 L flask , the final pressure will be

Options

A. 500 torr
B. 550 torr
C. 1000 torr
D. 1100 torr

Answer

To solve the problem, we can use the formula for the final pressure of gases when they are combined in a container. The formula is derived from the ideal gas law and is given by:

\[ P = \frac{P_1 \cdot V_1 + P_2 \cdot V_2}{V} \]

Where:
- \(P\) is the final pressure,
- \(P_1\) is the pressure of gas A,
- \(V_1\) is the volume of gas A,
- \(P_2\) is the pressure of gas B,
- \(V_2\) is the volume of gas B,
- \(V\) is the total volume of the flask.

### Step-by-step Solution:

1. **Identify the given values:**
- Gas A:
- Volume \(V_1 = 1 \, \text{L} = 1000 \, \text{mL}\)
- Pressure \(P_1 = 600 \, \text{torr}\)
- Gas B:
- Volume \(V_2 = 500 \, \text{mL}\)
- Pressure \(P_2 = 1000 \, \text{torr}\)
- Total volume of the flask \(V = 2 \, \text{L} = 2000 \, \text{mL}\)

2. **Substitute the values into the formula:**
\[ P = \frac{(600 \, \text{torr} \cdot 1000 \, \text{mL}) + (1000 \, \text{torr} \cdot 500 \, \text{mL})}{2000 \, \text{mL}} \]

3. **Calculate the numerator:**
- Calculate \(600 \cdot 1000 = 600000\)
- Calculate \(1000 \cdot 500 = 500000\)
- Add these two results:
\[ 600000 + 500000 = 1100000 \]

4. **Calculate the final pressure:**
\[ P = \frac{1100000 \, \text{torr}}{2000 \, \text{mL}} = 550 \, \text{torr} \]

5. **Conclusion:**
The final pressure in the 2 L flask after combining gas A and gas B is \(550 \, \text{torr}\).

### Final Answer:
The final pressure will be **550 torr**.