# Calculating Saturation Pressure and Specific Volume of Water at 256°C This solution involves two main steps: 1. **Finding the saturation pressure of water at 256°C** 2. **Finding the specific volume at this state** We'll use steam tables for calculations. --- 1. Finding Saturation Pressure at 256°C The *saturation pressure* is the pressure at which water boils at a given temperature. To find it at 256°C, refer to standard **steam tables** (IAPWS, or tables from thermodynamics textbooks). ### **Steam Table Excerpt (for reference):** | Temperature (°C) | Pressure (MPa) | Specific volume, \( v_g \) (m³/kg) | |------------------|----------------|-------------------------------------| | 255. | 3.7893 | .06839 | | 256. | 3.8577 | .06766 | | 257. | 3.9268 | .06694 | ### **From the Table** At **256°C**, the saturation pressure, \( P_{sat} \), is **3.8577 MPa**. --- ## 2. Calculating Specific Volume at Saturation The *specific volume* is the amount of volume per unit mass. At saturation, use the property \( v_g \) (for saturated vapor) from the steam table. ### **From the Table** At 256°C and 3.8577 MPa: - **Specific volume (\( v_g \))** = **.06766 m³/kg** --- ## 3. **Final Answers** - **Saturation pressure at 256°C:** \( P_{sat} = \boxed{3.8577~\text{MPa}} \) - **Specific volume at this state (saturated vapor):** \( v_g = \boxed{.06766~\text{m}^3/\text{kg}} \) --- ### **Summary Table** | Temperature (°C) | Saturation Pressure (MPa) | Specific Volume (\(v_g\)) (m³/kg) | |------------------|--------------------------|------------------------------------| | 256 | 3.8577 | .06766 | --- **Note:** Values are taken directly from standard steam tables; if you have access to different editions, minor differences may occur in the last digits. Always reference the most accurate tables available for engineering work.