Chemistry Lab 1- Gases

Question

High-pressure liquid chromatography (HPLC) is a method used in chemistry and biochemistry to purify chemical substances. The pressures used in this procedure range from around 500 kilopascals (500,000 Pa ) to about 60,000 kPa (60,000,000 Pa). It is often convenient to know the pressure in torr. If an HPLC procedure is running at a pressure of 7.95×10⁷ Pa , what is its running pressure in torr?

Answer 1

The most common conversions that one in chemistry will be familiar with are...

1 atm = 101.325 kPa

1 atm = 760 torr

Using these conversion factors to convert 7.95x10⁷ Pa to torr...

7.95x10⁷ Pa x 1 kPa/1x10³ Pa = 7.95x10⁴ kPa

7.95x104 kPa x 101.325 kPa/atm = 7.85x10² atm

7.85x10² atm x 760 torr/atm = 5.97x10⁵ torr

Alternatively, you could use the less common conversion factor that 1 Pa = 0.0075 torr...

7.95x10⁷ Pa x 0.0075 torr/1 Pa = 5.96x10⁵ torr