They are a set of conditions for pressure and temperature.
I assume that you want to know the difference between STP and NTP.
Both STP and NTP are a set of conditions that establish working temperature and pressure.
STP, or Standard Temperature and Pressure, conditions correspond to a temperature of
NTP, or Normal Temperature and Pressure, conditions correspond to a temperature of
A pressure of 1 atm is equivalent to 101.325 kPa.
This means that these two sets of conditions differ by
- Temperature - STP is
#0^@"C"#and NTP is #20^@"C"#
- Pressure - STP is 100 kPa and NTP is 101.325 kPa
When it comes to idel gases, these two conditions also differ in the volume occupies by 1 mole of gas - this is called the molar volume of a gas.
To show why that is, use the ideal gas law equation
- At STP conditions
This tells you that 1 mole of any ideal gas will occupy exactly
- At NTP conditions
This time, 1 mole of any ideal gas will occupy