Question

what happens when we combine hydrogen and oxygen to form water molecules? (draw what happens and then describe what happens.)

Explanation:

Hydrogen (diatomic $\text{H}_2$) and oxygen (diatomic $\text{O}_2$) undergo a chemical reaction where their covalent bonds break. New covalent bonds form between hydrogen and oxygen atoms, creating water molecules ($\text{H}_2\text{O}$). This is an exothermic reaction, releasing energy. The balanced chemical equation defines the stoichiometry of the reaction.

Diagram Description:

• Reactants: Two $\text{H}_2$ molecules (each with 2 H atoms bonded) and one $\text{O}_2$ molecule (2 O atoms bonded)
• Reaction: Bonds in $\text{H}_2$ and $\text{O}_2$ break; H atoms bond to O atoms
• Products: Two $\text{H}_2\text{O}$ molecules (each with 2 H atoms bonded to 1 O atom in a bent shape)

Answer:

1. Chemical Reaction & Equation: Hydrogen and oxygen undergo a synthesis (combustion) reaction to form water, following the balanced equation:

$$2\text{H}_2 + \text{O}_2 ightarrow 2\text{H}_2\text{O}$$

1. Atomic Process: The covalent bonds holding $\text{H}_2$ and $\text{O}_2$ molecules together break. Each oxygen atom forms covalent bonds with two hydrogen atoms, creating bent, polar $\text{H}_2\text{O}$ molecules.
2. Energy Change: The reaction is highly exothermic, meaning it releases significant heat and light energy.
3. Stoichiometry: 2 molecules of hydrogen gas react with 1 molecule of oxygen gas to produce 2 molecules of liquid (or gaseous) water.