Which of the following is NOT true about the thermodynamic standard state?
A. A pure liquid is in its standard state at 25C and a vapor pressure of 1.00 atm.
B. An aqueous solution is in its standard state at a concentration of 1.00 M.
C. A gas is in its standard state when its pressure is 1.00 atm and its temperature is 25C.
D. A solid is in its standard state when the atmospheric pressure is 1.00 atm and the temperature is 25C.
E. All of these are true.
The standard state for a gas is given in your chemistry textbook. The standard states for pure substances and solutes may also be given in the title of tables of thermodynamic properties. I think you can look this one up in your own textbook.
Good job contributing nothing GK. The answer is A.
To identify which statement is NOT true about the thermodynamic standard state, let's consider the definition of the standard state.
The thermodynamic standard state is a specific set of conditions that are used as a reference point for measuring the properties of substances. It is typically defined as the most stable form of a substance at a given temperature and pressure. The standard state conditions can vary depending on the substance and the context in which it is being used.
Now let's analyze each statement:
A. A pure liquid is in its standard state at 25C and a vapor pressure of 1.00 atm.
This statement describes the standard state of a pure liquid. It is commonly accepted that the standard state for a pure liquid is when it is at its boiling point at a pressure of 1.00 atm. Therefore, statement A is consistent with the definition of the thermodynamic standard state.
B. An aqueous solution is in its standard state at a concentration of 1.00 M.
This statement describes the standard state of an aqueous solution. In general, the standard state for an aqueous solution is defined as a concentration of 1.00 M. This concentration is often chosen as a reference point for measuring the properties of solutions. So, statement B is also consistent with the definition of the thermodynamic standard state.
C. A gas is in its standard state when its pressure is 1.00 atm and its temperature is 25C.
This statement describes the standard state of a gas. The standard state for a gas is defined as a pressure of 1.00 atm and a temperature of 25C. This specific combination of pressure and temperature is chosen as a reference point for measuring the properties of gases. Hence, statement C is consistent with the definition of the thermodynamic standard state.
D. A solid is in its standard state when the atmospheric pressure is 1.00 atm and the temperature is 25C.
This statement describes the standard state of a solid. However, the definition of the thermodynamic standard state for a solid is not based on atmospheric pressure or temperature. Instead, it is defined as the most stable form of the solid under a given set of conditions. So, statement D is NOT true about the thermodynamic standard state.
E. All of these are true.
Since statement D is not true, option E is also incorrect.
In conclusion, the statement that is NOT true about the thermodynamic standard state is D. A solid is in its standard state when the atmospheric pressure is 1.00 atm and the temperature is 25C.