Re: Would I be right in saying that 1 jar of sugar could be '1 mole' of sugar?

This is similar to some other questions I've answered previously about salt and water, so I'll start with the same basic calculations. Common table sugar is sucrose, which has a molecular mass of 342.3 grams per mole. Assuming you're using granulated sugar, one grain of sugar has a mass around 0.625 mg (5/8 of a milligram), as measured by the analytical balance in our lab. So, one grain is 1.82588 x 10^-6 moles or around 1.8 µM (micromoles). As you said, Avogadro's Number is 6.022 x 10²³ molecules per mole, so a single grain of sugar contains 1.09954 x 10¹⁸ molecules of sucrose, or 1.1 quintillion molecules per grain of sugar (in American terms).

Also, one cubic centimeter of sucrose (again using the analytical balance) has a mass around 950 mg, which is a little over 1,500 grains. I don't know how big your sugar jar is, but if it holds about half of a liter (just over a pound of sugar), that would be around 750,000 grains - for demonstration purposes, you could use a little more sugar and call it a million grains. So, the number of molecules of sucrose in a single grain of sugar is the same as the number of sugar grains in a million million jars of sugar. (That's one trillion US or one billion UK.) I like the concept of explaining molecules this way, and for younger students, I think this would be completely acceptable, since you would be conveying the basic idea of many tiny things making up one unit; however, for older students with better grasps of large numbers, I think the idea of millions of millions of jars of sugargrains in a single tiny crystal is more staggering and provocative.