**Question 1**

Electron mass = 9.1093897 x 10^-28g

Proton mass = 1.6726231 x 10^-24g

Neutron mass = 1.6749286 x 10^-24g

Using the examples of Li-7 (atomic mass 6.9) and B-11 (atomic mass 10.8) & using the above information, prove that the approx. value of Avogadro's number is 6 x 10^23. Also state with justification any assumptions you may have made.

**Question 2**

Think of 5 questions for which the answer is 2 moles, and arrange them in increasing order of difficulty. Also include the full solutions to these questions.

I'd appreciate it greatly if anyone could explain how I should go about doing Question 1. As for Question 2, as I'm an O/A Levels student, I'd prefer slightly less complex questions, but still reasonably challenging. Of course, you don't have to give me 5 questions at one go. One will do =)

Thanks in advance!