Question

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

Answer 1

Answer:

0.171 grams of oxygen combined with the metal.

Explanation:

$2Mg+O_2\rightarrow 2MgO$

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.