Properties of Pure Substances · Thermodynamics · GATE ME

The INCORRECT statement about the characteristics of critical point of a pure substance is that

For an ideal gas with constant values of specific heats, for calculation of the specific enthalpy,

A rigid container of volume $$0.5$$ $${m^3}$$ contains $$1.0$$ $$kg$$ of water at $${120^ \circ }C$$
$$\left( {{V_f} = 0.00106\,{m^3}/kg,\,\,{v_g} = 0.8908\,\,{m^3}/kg} \right).$$ The state of water is

A pure substance at $$8$$ $$MPa$$ and $${400^ \circ }C$$ is having a specific internal energy of $$2864$$ $$kJ/kg$$ and a specific volume of $$0.03432\,{m^3}/kg.$$ Its specific enthalpy (in $$kJ/kg$$) is ____________

Water has a critical specific volume of $$0.003155$$ $${m^3}/kg.$$ A closed and rigid steel tank of volume $$0.025{m^3}$$ contains a mixture of water and steam at $$0.1MPa.$$ The mass of the mixture is $$10$$ $$kg.$$ The tank is now slowly heated. The liquid level inside the tank.

When wet steam flows through a throttle valve and remains wet at exit

Constant pressure lines in the super-heated region of the Mollier diagram will have

The relationship $$\,{\left( {\partial T/{\partial _p}} \right)_h} = 0$$ holds good for :

During the phase change of a pure substance:

At the point of a pure substance, the number of degrees of freedom is :

In Fe-Fe₃C phase diagram, the eutectoid composition is 0.8 weight % of carbon at 725 ºC. The maximum solubility of carbon in α-ferrite phase is 0.025 weight % of carbon. A steel sample, having no other alloying element except 0.5 weight % of carbon, is slowly cooled from 1000 ºC to room temperature. The fraction of pro-eutectoid α-ferrite in the above steel sample at room temperature is

Steam enters a turbine at $$30bar,$$ $${300^ \circ }C$$ $$\left( {u = 2750\,\,kJ/kg,\,\,h = 2993\,\,kJ/kg} \right)$$ and exits the turbine as saturated liquid at $$15$$ $$kPa$$ $$\left( {u = 225\,\,kJ/kg,\,\,h = 226\,\,kJ/kg} \right)$$.
Heat loss to the surrounding is $$50$$ $$kJ/kg$$ of steam flowing through the turbine. Neglecting changes in kinetic energy and potential energy, the work output of the turbine (in $$kJ/kg$$ of steam) is _____________

In the figure shown, the system is a pure substance kept in a piston- cylinder arrangement. The system is initially a two- phase mixture containing $$1$$ $$kg$$ of liquid and $$0.03$$ $$kg$$ of vapour at a pressure of $$100kPa.$$ Initially, the piston rests on a set of stops, as shown in the figure. A pressure of $$200kPa$$ is required to exactly balance the weight of the piston and the outside atmospheric pressure. Heat transfer takes place into the system until its volume increases by $$50\% $$. Heat transfer to the system occurs in such a manner that the piston, when allowed to move, does so in a very slow (quasi-static / quasi-equilibrium) process. The thermal reservoir from which heat is transferred to the system as a temperature of $${400^ \circ }C$$. Average temperature of the system boundary can be taken as $${175^ \circ }C.$$ Heat transfer to the system is $$1kJ$$, during which its entropy increases by $$10$$ $$J/K.$$

Specific volume of liquid $$\left( {{v_f}} \right)$$ and vapour $$\left( {{v_g}} \right)$$ phases, as well as values of saturation temperatures, are given in the table below.

The work done by the system during the process is

In the figure shown, the system is a pure substance kept in a piston- cylinder arrangement. The system is initially a two- phase mixture containing $$1$$ $$kg$$ of liquid and $$0.03$$ $$kg$$ of vapour at a pressure of $$100kPa.$$ Initially, the piston rests on a set of stops, as shown in the figure. A pressure of $$200kPa$$ is required to exactly balance the weight of the piston and the outside atmospheric pressure. Heat transfer takes place into the system until its volume increases by $$50\% $$. Heat transfer to the system occurs in such a manner that the piston, when allowed to move, does so in a very slow (quasi-static / quasi-equilibrium) process. The thermal reservoir from which heat is transferred to the system as a temperature of $${400^ \circ }C$$. Average temperature of the system boundary can be taken as $${175^ \circ }C.$$ Heat transfer to the system is $$1kJ$$, during which its entropy increases by $$10$$ $$J/K.$$

Specific volume of liquid $$\left( {{v_f}} \right)$$ and vapour $$\left( {{v_g}} \right)$$ phases, as well as values of saturation temperatures, are given in the table below.

At the end of the process, which one of the following situations will be true?

In the figure shown, the system is a pure substance kept in a piston- cylinder arrangement. The system is initially a two- phase mixture containing $$1$$ $$kg$$ of liquid and $$0.03$$ $$kg$$ of vapour at a pressure of $$100kPa.$$ Initially, the piston rests on a set of stops, as shown in the figure. A pressure of $$200kPa$$ is required to exactly balance the weight of the piston and the outside atmospheric pressure. Heat transfer takes place into the system until its volume increases by $$50\% $$. Heat transfer to the system occurs in such a manner that the piston, when allowed to move, does so in a very slow (quasi-static / quasi-equilibrium) process. The thermal reservoir from which heat is transferred to the system as a temperature of $${400^ \circ }C$$. Average temperature of the system boundary can be taken as $${175^ \circ }C.$$ Heat transfer to the system is $$1kJ$$, during which its entropy increases by $$10$$ $$J/K.$$

Specific volume of liquid $$\left( {{v_f}} \right)$$ and vapour $$\left( {{v_g}} \right)$$ phases, as well as values of saturation temperatures, are given in the table below.

The net entropy generation (considering the system and the thermal reservoir together) during the process is closest to

Given below is an extract from steam tables.

Specific enthalpy of water in $$kJ/kg$$ at $$150$$ bar and $$ {45^ \circ }C$$ is

The following table of properties was printed out for saturated liquid and saturated vapour of ammonia. The titles for only the first two columns are available. All that we know is that the other columns (columns $$3$$ to $$8$$) contain data on specific properties, namely, internal energy $$(kJ/kg),$$ enthalpy $$(kJ/kg)$$ and entropy $$(kJ/kg.K).$$

The specific enthalpy data are in columns

The following table of properties was printed out for saturated liquid and saturated vapour of ammonia. The titles for only the first two columns are available. All that we know is that the other columns (columns $$3$$ to $$8$$) contain data on specific properties, namely, internal energy $$(kJ/kg),$$ enthalpy $$(kJ/kg)$$ and entropy $$(kJ/kg.K).$$

When saturated liquid at $${40^ \circ }C$$ is throttled to $$ - {20^ \circ }C,$$ the quality at exit will be

A vessel of volume $$\,\,1.0\,\,{m^3}$$ contains a mixture of liquid water and steam in equilibrium at $$1.0$$ bar.Given that $$90\% $$ of the volume is occupied by the steam, find the dryness fraction of the mixture. Assume, at $$1.0$$ bar, $${\,{v_f} = 0.001\,\,{m^3}/kg}$$ and $${\,{v_g} = 1.7\,\,{m^3}/kg}.$$

In the vicinity of the triple point, the vapour pressures of liquid and solid ammonia are respectively given by
$$\eqalign{ & \ln \,\,P = 15.16 - 3063/T \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,and \cr & \ln \,\,P = 18.70 - 3754/T \cr} $$

Where $$p$$ is in atmospheres and $$T$$ is in Kelvin. What is the temperature at the triple point.