A gas cylinder contains 15 moles of 02. How many molecules of oxygen are in the cylinder

The answer is 9.03 * 10²⁴ molecules of oxygen!

Step 1 6.02 * 10²³ molecules : 1 mol = x : 15 mol Step 2 x = 6.02 * 10²³ molecules * 15 mol * 1 mol Step 3 x = 90.3 * 10²³ molecules Step 4 x = 9.03 * 10 * 10²³ molecules Step 5 x = 9.03 * 10²³⁺¹ molecules Step 6 { x = 9.03 * 10²⁴ molecules }