Question

A volume of 56.0 mL of He at STP. a. How much weight? b. How many molecules?

Answer 1

Number of moles = 0.0025 mol

Explanation:

Given that,

The volume of He at STP is 56.0 ml

Part a:

Find the mole

According to the standard conversion

1 mol = 22.4L

Firstly, we need to convert 56.0ml to L

This can be done by dividing by 1000

56.0mL = 0.056L

1 mole = 22.4L

x mole = 0.056L

Cross multiply

1 * 0.056 = x * 22.4

0.056 = 22.4x

Divide both sides by 22.4

x = 0.056 / 22.4

x = 0.0025 mole

Hence, the mole of Helium is 0.0025 moleHe