What is the definition of consideration?

consideration: promise or performance that the promisor demands as the price of the promise.

5. Is there a difference between promising to give a person a gift and promising to make a gift to a charity? Assume that both the individual and the charity rely on your promise to fund future purchases.

6. What is the difference between past performance and pre-existing legal obligation? Give an example of each? Will either serve as valid consideration to support a contract?