Question

Which of the following samples will have the lowest pressure if they are all at the same temperature and in identical containers (same volume)?
a. 15 g Ne
b. 15 g
c. 15 g Kr
d. 15 g CO2
e. 15gF2
f. All of these samples will have the same pressure.

Answer 1

Answer:

c. 15 g Kr

Explanation:

The amount of a gas (Moles) is directely proportional to its pressure. That means the higher amount of moles, the highest pressure and vice versa.

Using molar mass of the compounds (Ne=20.2g/mol, Ar = 39.9g/mol, Kr = 83.8g/mol, CO₂ = 44 g/mol and F₂ = 38.0g/mol), moles of 15.0g of each gas are:

Ne = 15g ₓ (1mol / 20.2g) = 0.74 moles of Ne

Ar = 15g ₓ (1mol / 39.9g) = 0.38 moles of Ar

Kr = 15g ₓ (1mol / 83.8g) = 0.18 moles of Kr

CO₂ = 15g ₓ (1mol / 44g) = 0.34 moles of CO₂

F₂ = 15g ₓ (1mol / 38g) = 0.39 moles of F₂

As 15g of Kr contains the less quantity of moles, this sample will con have the lowest pressure