In a hydrogen fuel cell, hydrogen gas and oxygen gas are combined to form water. write the balanced chemical equation describing this reaction (using lowest whole-number coefficients.

2H₂ + O₂ → 2H₂O

Explanation:

The problem tells us that hydrogen gas (H₂) and oxygen gas (O₂) are the reactants, while water (H₂O) is the only product. Thus, the reaction is:

H₂ + O₂ → H₂O

In order to balance this equation, we begin with counting the atoms of O present in the left side and in the right side of the equation. Because there are two O atoms in the left but only one on the right, we add a coefficient of 2 in the right side:

H₂ + O₂ → 2H₂O

Now we count the H atoms, there are 2 in the left and 4 in the right, so we add a coefficient of 2 for the hydrogen gas:

2H₂ + O₂ → 2H₂O

Now there are 4 H atoms in both sides, and 2 O atoms in both sides, so the equation is balanced.

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error