Describe two or three ways that you could determine whether the powder is a compound or a mixture?

Answer 1

Here are a few...

While compounds are elements that have been chemically combined, mixtures are elements that have been physically combined- for example, H20 (regular water) is a compound, whereas saltwater is a mixture.

As such, compounds can only be separated by chemical means, whereas mixtures can be separated by physical means. (In the water-saltwater scenario, water can only be separated into hydrogen and oxygen by using electricity or some similar method, whereas saltwater can be separated into salt and water simply by leaving the saltwater in a place where the water can evaporate.) The same basic methods apply to your powder. (A hint: If your powder is a collection of several differently colored particles, or some particles are denser than others, it is most likely a mixture.)

Most compounds have properties that are different from their component elements. (water, for example, can be used to extinguish fires, while both oxygen and hydrogen are highly flammable elements.) Most mixtures, on the other hand, retain the same basic properties of their components. (Saltwater can be used to put out a fire just as easily as water can.)

Compounds also always contain the same ratio of component atoms- for instance, in water (H20) there will always be 2 hydrogen molecules bonded with 1 oxygen molecule for each water molecule. There will never be 3 hydrogen molecules and 5 oxygen molecules, and so on. A mixture has a variable composition.

I hope this helped. If you need a more in-depth explanation, especially for actually separating the components of your powder, try visiting http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mixtures.html