Is a silver coin a compound?

Answer 1

No, silver coins are alloys.

A compound is composed of two or more elements combined at the atomic level. The ratio of one element to the other(s) is always fixed. Water is the most familiar and classic example of a compound. It's composed of two gases, oxygen and hydrogen, with one atom of oxygen joined to two of hydrogen at the atomic level - i.e. H20. A compound can only be separated into its component elements via a chemical process; for example water is usually separated by a process called electrolysis.

An alloy is a combination of two or more metals, usually created by melting them and mixing them together. The proportions can vary depending on how much of each metal went into the mix. For example, coin silver is 90% silver and 10% copper, sterling silver is 92.5% silver and 7.5% copper, US cupronickel coins are 25% nickel and 75% copper, and so on. Alloys can frequently be separated into their component metals by mechanical processes such as heating or the use of acids.