Question

experiment #2
based on the law of conservation of mass, predict the minimum amount of magnesium that will react with all 16.0 grams of oxygen to produce 40.3 grams of magnesium oxide.
magnesium + oxygen -----> magnesium oxide
□g + 16.0 g ----> 40.3 g
experiment #3 assuming that magnesium and oxygen will react completely with one another, predict the mass of magnesium oxide that will be produced.
magnesium + oxygen -----> magnesium oxide
12.2 g + 8.0 g ----> □g

Explanation:

Step1: Apply the Law of Conservation of Mass for Experiment #2

According to the law, mass of reactants = mass of products. Let the mass of magnesium be $x$. So $x + 16.0=40.3$.

Step2: Solve for the mass of magnesium

$x=40.3 - 16.0$.
$x = 24.3$ g.

Step3: Apply the Law of Conservation of Mass for Experiment #3

The mass of magnesium oxide produced is the sum of the mass of magnesium and oxygen. Mass of magnesium = 12.2 g, mass of oxygen = 8.0 g. So mass of magnesium oxide = $12.2+8.0$.

Step4: Calculate the mass of magnesium oxide

$12.2 + 8.0=20.2$ g.

Answer:

Experiment #2: 24.3 g
Experiment #3: 20.2 g