Question

how many moles of helium would you find in a birthday balloon that had a volume of 6.2 l? assume conditions are at stp
a. 0.28 moles
b. 3.6 moles
c. 12 moles
d. 22.4 moles

Explanation:

Step1: Recall STP molar volume

At STP, 1 mole of gas = $22.4\ \text{L}$

Step2: Calculate moles of helium

Moles = $\frac{\text{Given Volume}}{\text{Molar Volume at STP}}$
$\text{Moles} = \frac{6.2}{22.4}$

Step3: Compute the value

$\text{Moles} \approx 0.28$

Answer:

A. 0.28 moles