This question is about Avogadro's number.
Avogadro's number is the number is 6.022 * 10^23.
That means that 1 mol of molecules is 6.022 * 10^23 molecules, so 4 moles is 4 * 6.022 * 10^23 molecules = 24.088 * 10^23 molecules = 2.4088 * 10^24 molecules.
Answer: 2.4088 * 10^24 molecules.