Answer to Question #25627 in Physical Chemistry for Paige

Question

A sample of N2 has 1.70 moles and occupies 3.80 l at 25.0˚C.
A) What volume will it occupy with 2.60 moles?
B) How many moles are in a sample that occupies 1.45 L?

Answer 1

According to the ideal gas law:

pV=nRT

p – pressure (atm)

V – volume (L)

n – amount (moles)

R – universal gas constant

T – temperature (K)

P, R, T – don’t change, that’s why we can writea proportion

V₁/V₂ = n₁/n₂

a) What volume will it occupy with 2.60 moles?
V₂ = V₁ x n₂ / n₁
V₂ = 3.80 x 2.60 / 1.70 = 5.81 L
Answer: V₂ = 5.81 L

b) How many moles are in a sample that occupies 1.45 L?
n₂ = n₁ x V₂ / V₁ = 1.70 x 1.45 / 3.80 = 0.65 mol
Answer: n₂ = 0.65 mol