Thermodynamics: Entropy and Enthalpy

This video tutorial by Graphics explains how to solve a problem involving the determination of enthalpy and entropy of steam. It covers the conversion of pressure units from megapascal to kilopascal and bar, the calculation of the dryness fraction using specific volume data, and the subsequent calculations of enthalpy and entropy using steam table data. The tutorial provides a step-by-step approach to understanding the relationships between these thermodynamic properties and the use of steam tables.

What is the initial pressure of steam given in the problem?

• 0.7 megapascal

• 7 bar

• 700 kilopascal

• 0.07 megapascal

How do you convert 0.7 megapascal to kilopascal?

• Multiply by 100

• Multiply by 1000

• Divide by 1000

• Add 1000

What is the equivalent of 0.7 megapascal in bar?

• 7 bar

• 0.7 bar

• 70 bar

• 700 bar

What is the dryness fraction used for in the calculation?

• To calculate enthalpy and entropy

• To find the temperature

• To calculate the pressure

• To determine the specific volume

Which formula is used to calculate the dryness fraction?

• H = HF + x(HG - HF)

• T = TF + x(TG - TF)

• P = PF + x(PG - PF)

• V = VF + x(VG - VF)

What does a dryness fraction of 1 indicate?

• Mixture of gas and liquid

• Pure liquid

• Pure gas

• No substance

What is the relationship between enthalpy at liquid and gaseous states?

• H = HF + x(HG - HF)

• H = HG + x(HF - HG)

• H = HG - x(HF + HG)

• H = HF - x(HG + HF)

What is the calculated enthalpy of the steam system?

• 2.741522 KJ/kg

• 27415.22 KJ/kg

• 274.1522 KJ/kg

• 2741.522 KJ/kg

What is the formula used to calculate entropy?

• S = SG + x(SF - SG)

• S = SF + x(SG - SF)

• S = SF - x(SG + SF)

• S = SG - x(SF + SG)

What is the calculated entropy of the steam system?

• 665.8 K/kg

• 66.58 K/kg

• 0.6658 K/kg

• 6.658 K/kg