A student burned 0.250 g of magnesium metal in an open crucible. Oxygen from the air combined with the metal forming magnesium oxide. If 0.421 g of magnesium oxide were produced, what mass of oxygen combined with the metal? 1. 0.171 g 2. 0.671 g 3. 1.684 g 4. 0.594 g

0.171 grams of oxygen combined with the metal.

Explanation:

Mass of magnesium oxide produced = 0.421 g

Mass of magnesium metal used = 0.250 g

Suppose reaction completely converts the magnesium into magnesium oxide.

Mass of oxygen combined with magnesium = m

0.421 g = 0.250 g + m

m =  0.421 g - 0.250 g = 0.171 g

0.171 grams of oxygen combined with the metal.

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.