Lesson in Chocolate
Chocolate will stay fresh for about a year if kept in a cool, dry place. Dark chocolate can be stored even longer.
Sometimes chocolate develops white or gray "blooms" on its surface. This just means that the cocoa butter has separated. While it doesn't look pretty, the chocolate is still fine to use.
Chocolate can scorch over high heat (generally above 115°). It's better to melt chocolate slowly in the microwave or over low-heat in a double boiler.
When microwaving chocolate, keep in mind that chips and chunks may still appear formed and unmelted after heating but will be fluid upon stirring.
Water can make chocolate seize so always use dry utensils and pans.