Converting units of measure for gas pressure is just like doing conversion of :

Mg ---> g ---> to ---> moles ---> atoms

Review my tutorial on that in the tutorial: Grams to moles to atoms - Tutorial or PDF

There are bridges for these conversions just as there were for those. Everything is based on 4 basic equalities:

1 atm = 760 mmHg

1 atm = 760 Torr

1 atm = 101,325 Pa

1 atm = 14.69 psi

Converting from anything to
anything else requires you to make one or all of the equalities above into
fractions. The top of the fraction will
always be what you are converting to.

**Example**: Convert 56 psi to atm’s.

__bridge__

56
psi 1 atm

------ x
---------- = **3.81 atm**

1
14.69 psi

Now let’s do an example of going
through several steps:

**Example**: Convert
25,000 Pa’s to Torr.

__bridge____bridge__

25,000
Pa 1 atm 760 Torr

----------- x
------------- x ------------- = **187.52
Torr**

1 101,325 Pa 1 atm

Each bridge, or operation, is determined by where we start from and where we are going.

** If you want to check your
work** and see that you came out to the right answer, check out the conversion-calculator
web sites, see which one you prefer:

Converter CALCULATOR – all types of units of measure conversions – applet (Berkley)

Converter for units of measure used in gas laws - USC

The odd problems do not have answers in the back of the
book, but you can check them out with this little calculator. All you have to do is put in the unit of
measure you are starting with and then hit your tab key. The calculator will give you all the other
units of measure and their correct quantities.
To activate the calculator, click on “Click __Here__” You will find it on the left-hand side of
the page ¾ of the way down. After you
activate the calculator enlarge it to full page. Under the ** Type of Conversion**
(see upper left of screen), change the conversion type to pressure on the
drop-down menu. Now you’re ready to go.

**Example: using this calculator (link also shown above)
**

Converter CALCULATOR – all types of units of measure conversions – applet (Berkley)

__Problem__

Convert 25,000 Pa to Torr (see problem above and then check the answer I gave with the calculator.

__Solution__

Click on Pascal as ** Original Units
. **Next, enter 25,000 on the
calculator keyboard. The number you
enter will be small and will be top center of the screen.

Now click ** torr** in the

**Answer:**

**187.516 **which represents **187.52**
when rounded.