# Question #af461

##### 1 Answer

They are a set of conditions for pressure and temperature.

#### Explanation:

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 **273.15 K**, and a pressure of **100 kPa**.

**NTP**, or *Normal Temperature and Pressure*, conditions correspond to a temperature of **293.15 K**, and a pressure of **1 atm**.

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