Atoms can combine with atoms of the same element (for example, oxygen, hydrogen or a lump of carbon). The number of different combinations of atoms (making compounds) is vast. From only about 100 elements we get the millions of different materials we see around us every day.
Where Refunds Apply. The Steam refund offer, within two weeks of purchase and with less than two hours of playtime, applies to games and software applications on the Steam store. Here is an overview of how refunds work with other types of purchases.
As I said, it seems to take about 2 hours for Steam to realize the money really isn't coming and switch to failed, after which you can try the transaction again with no ill effects or being double billed. I've had it happen several times, during holiday sales.