A compound is a pure substance that contains two or more elements chemically bonded together in a fixed ratio. A mixture is a combination of two or more substances that are not chemically bonded together and can be separated by physical means.

Buttered popcorn is a mixture of popcorn kernels, butter, and salt. The popcorn kernels are a mixture of starch, protein, and fiber. The butter is a mixture of fat, water, and protein. The salt is a compound of sodium and chloride.

When popcorn is popped, the starch in the kernels gelatinizes and expands, causing the kernels to puff up. The butter and salt are added after the popcorn is popped. The butter melts and coats the popcorn kernels, and the salt adds flavor.

Buttered popcorn is a delicious and popular snack, but it is not a compound. It is a mixture of several different substances.