Question

An ideal gas has a pressure of 2.5 atm, a volume of 1.0 L at a temperature of 30°C. How many molecules are there in this gas? (R = 8.31 J/mol ∙ K,1.00 atm = 101 kPa, NA = 6.022 × 1023)

Answer 1

Answer:

In the gas there are 6.02x10²² molecules

Explanation:

This is a problem to be solved by the Ideal Gas Law formula, which is this one:

Pressure . volume = n° moles . R . T° in K

The excersise presented R as 8.31 J/mol, but If i follow the others data, I'd rather use 0.082 L.atm / mol.K

Let's replace numbers:

2.5 atm . 1L = n° moles. 0.082L.atm / mol.K . 303K

(2.5 atm . 1L) / (0.082 mol.K/L.atm . 303K) = n° moles

0.100 moles = n

Now that we have the moles, we can use NA to calculate the total of molecules:

1 mol ___ has __ NA molecules

0.1 mol has ____ ( 0.1 . 6.02x10²³) = 6.02x10²² molecules