# Chemical Terms Getting Started

This page is a quick-start guide that helps you get started with the Chemical Terms language:

# Use Chemical Terms for calculations

Let's see how to calculate some basic properties of aspririn.

The applied Chemical Terms expressions are as follows:

`mass`

`logP`

These calculations return *180.16* and *1.24* as mass and logP of aspirin, respectively.

# Define filters

The Chemical Terms expressions can also be used to filter molecules for which the investigated properties can be calculated prior to filtering.

We list here two simple rules. The first one defines that the mass of the compounds should be less than 500, whereas the second one states that the logP should be not greater than 5.

`mass<=`

`500`

`logP<=`

`5`

Accordingly, mathematical symbols like greater than, less than can be applied conventionally in Chemical Terms.

# Link different expressions

The defined filtering conditions may be linked by logical operators.

For example, to specify that the calculated log P of a compound is between -0.4 and 5.6 and the molecular weight is between 160 and 480, the following expression should be formulated:

`logP>=-`

`0.4`

` AND logP<=`

`5.6`

` `

`AND mass>=`

`160`

` AND mass<=`

`480`

Both properties should be included twice as two conditions were defined for each property.

Other logical operators such as OR, NOT can be used analogous to AND.