Vitamin A has a molar mass of 286.4 g/mol and has a general molecular formula of CxHyE, where is an unknown element. If vitamin A is 83.96% C and 10.56 % H by mass, what is the molecular formula of vitamin A?

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy