Question

1. a student created the model below to show the reaction of methane (ch₄) with oxygen (o₂). ch₄ + 2o₂ → 2h₂o + co₂ what change would make the students model correctly show the law of conservation of mass? remove one hydrogen atom from the reactants so they match the number in the products. add one more carbon atom to the reactants so the number of carbons matches the products. add two more oxygen atom to the products so the number of oxygen atoms is the same on both sides. take away one oxygen molecule from the reactants so the numbers balance on both sides.

Explanation:

Step1: Analyze reactant and product atoms

In the reaction $CH_4 + 2O_2
ightarrow2H_2O + CO_2$, on the reactant side: 1 carbon atom, 4 hydrogen atoms, and 4 oxygen atoms. On the product side: 1 carbon atom, 4 hydrogen atoms, and 4 oxygen atoms. The molecular - model shown has an incorrect depiction.

Step2: Check each option

• Removing one hydrogen atom from reactants will unbalance hydrogen atoms.
• Adding one more carbon atom to reactants will unbalance carbon atoms.
• Adding two more oxygen atoms to products will unbalance oxygen atoms.
• The correct action is to take away one oxygen molecule from the reactants. Currently, the model has an extra oxygen molecule in the reactant - side depiction.

Answer:

Take away one oxygen molecule from the reactants so the numbers balance on both sides.