Why a cut apple wrapped in foil does not turn brown?

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

Which item is most likely part of the safety contract

In a chemical reaction, the final amount of the products is determined by the a. universal gas law b. law of definite proportions c. air pressure d. temperature e. none of the above me