Standard ambient temperature and pressure

At standard ambient temperature and pressure (SATP), which means exactly 25°C (298.15 K) and exactly 1 bar, the conditions commonly used to report data in chemistry, the molar volume of an ideal gas is 24.79 L-mol l, which is about the volume of a cube l ft on a side (Fig. 4.15). The expression standard temperature and pressure (STP) means 0°C and 1 atm (both exactly), the conditions formerly used to report data and still widely used in some calculations. At STP, the molar volume of an ideal gas is 22.41 I.-mol1. Note the slightly smaller value the temperature is lower and the pressure is slightly higher, and so the same amount of gas molecules occupies a smaller volume than at SATP. 

The amount of permeated substance can be expressed in mass, mole or volume units. For gases, volume is preferred, expressed as the amount permeating under conditions of standard temperature and pressure (STP), which corresponds to the standard temperature of 273.15 K and standard pressure of 1.01325 105 Pa. The corresponding dimensions for D and S are obtained at the same time from Eq. (9-4). The standard ambient temperature and pressure (SATP) are set at p°= 1 bar= 105 Pa = 0.9678 atm and T = 298.15 K. The data in handbooks however is still mostly expressed with p = 1 atm as standard pressure. For practical purposes the difference between these two conventions is insignificant compared to the variability of the materials themselves. 

The average pressure of the atmosphere at sea level is taken as standard pressure (760 mm Hg = 760 torr = 1 atm = 101.3 kPa). The freezing point of water (0°C or 273 K) is defined as standard temperature. Together, these conditions are referred to as standard temperature and pressure (STP). (See Figure 11.23.) The normal conditions under which we live are referred to as standard ambient temperature and pressure. These conditions are known as SATP, defined as 25°C and 100 kPa. 

Under what conditions might you use standard ambient temperature and pressure as a reference rather than standard temperature and pressure ... 

Use the ideal gas law to calculate the molar volume of a gas at standard ambient temperature and pressure (SATP). The conditions for SATP are 298 K and 100 kPa. 

Molar entropy depends upon both temperature and pressure. For this reason, an additional stipulation is necessary if the values are to be tabulated. In chemistry, one generally refers to standard conditions, i.e., 298 K (more precisely 298.15 K) and 100 kPa [this corresponds to room temperature of 25 °C and normal air pressure, so-called standard ambient temperature and pressure (SATP)]. For characterizing the standard values, we use the symbol , so for example,... 

In order to characterize the chemical reactivity of an element, the formation free energy (AFc ) of its chloride (10) was taken into account. The values were computed for the standard ambient temperature and pressure (298 K,... 

It is useful to define a set of reference state variables for gases, because they can have a wide range of values that can in turn affect other state variables. The most common set of reference state variables for pressure and temperature isp = 1.0 bar and T = 273.15 K = 273.15°C. These conditions are called standard temperature and pressure, ahhcevvated STP. Much of the thermodynamic data reported for gases are given for conditions of STP. SI also defines standard ambient temperature and pressure, SATP, as 298.15 K for temperature and 1 bar for pressure (1 bar = 0.987 atm). 

Fig. 3.1.4. Particle tracks in a cyclone by computational fluid dynamics. The swirl components are not shown. On the left 10 tracks are calculated from the mean flow field on the right 5 particle tracks are shown where the response to the turbulent motion of the gas is taken into account. Conditions cyclone diameter 20 cm, gas inlet velocity 15 m/s, gas at SATP ( standard ambient temperature and pressure , 25 C and 1 atm), particle density 2730 kg/m ...

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