Question

A chemist is preparing to carry out a reaction that requires 5.75 moles of hydrogen gas. The chemist pumps the hydrogen into a 10.5 L rigid steel container at 20.0 °C. To what pressure, in kPa, must the hydrogen be compressed? (Show all work for full credit and circle your final answer) *

Answer 1

The hydrogen must be compressed to 1333.13302 kPa.

Step-by-step explanation:

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P * V = n * R * T

In this case:

• P= ?
• V= 10.5 L
• n= 5.75 moles
• R= 0.082
  `(atm*L)/(mol*K)`
• T= 20 C= 293 K (being 0 C= 273 K)

Replacing:

P* 10.5 L= 5.75 moles* 0.082
`(atm*L)/(mol*K)` * 293 K

Solving:

`P=(5.75 moles* 0.082 (atm*L)/(mol*K) * 293 K)/(10.5 L)`

P= 13.157 atm

If 1 atm is equal to 101.325 kPa, then 13.157 atm is equal to 1333.13302 kPa.

The hydrogen must be compressed to 1333.13302 kPa.