Hydrazine \(\left(\mathrm{N}_{2} \mathrm{H}_{4}\right)\) and dinitrogen tetroxide \(\left(\mathrm{N}_{2} \mathrm{O}_{4}\right)\) form a self-igniting mixture that has been used as a rocket propellant. The reaction products are \(\mathrm{N}_{2}\) and \(\mathrm{H}_{2} \mathrm{O}\) . (a) Write a balanced chemical equation for this reaction. (b) What is being oxidized, and what is being reduced? (c) Which substance serves as the reducing agent and which as the oxidizing agent?

Understanding a balanced chemical equation is a fundamental skill in chemistry. Just like in our example with rocket propellants, balancing a reaction involves ensuring that the number of atoms for each element is the same on both sides of the equation. This represents the conservation of mass, indicating that atoms are neither created nor destroyed in a chemical reaction.

Let's take a closer look at how to balance the equation step by step. Start with a list of all reactants and products. Then, write out the unbalanced chemical equation. Next, using coefficients, adjust the number of molecules to ensure that for every element, the atom count is the same on each side.

For instance, the propellant example required balancing nitrogen and hydrogen atoms. The final equation, \[\text{2 N}_{2}\text{H}_{4}+\text{N}_{2}\text{O}_{4}\rightarrow\text{3 N}_{2}+\text{8 H}_{2}\text{O} \], shows that we have equal numbers of nitrogen (seven on each side) and hydrogen (eight on each side) atoms, which is key to a correctly balanced equation.

Oxidation and reduction are two halves of the same reaction, always occurring together during a process called redox. Oxidation refers to the loss of electrons, while reduction is all about the gain of electrons. To determine which occurs in a given reaction, you'll need to assign oxidation states to each element both before and after the reaction.

In the rocket propellant equation, nitrogen's oxidation state changes, which clues us into what's oxidized and what's reduced. Remember, a more positive oxidation state means oxidation, and a more negative means reduction. For the propellant reaction, hydrazine's nitrogen goes from an oxidation state of -2 to 0, signifying oxidation. Conversely, dinitrogen tetroxide's nitrogen goes from +4 to 0, signifying reduction.

Identifying the reducing and oxidizing agents is a crucial step because these agents are what drive the chemical reaction forward. The reducing agent is the 'giver,' it loses electrons and itself gets oxidized. On the flip side, the oxidizing agent is the 'taker,' it gains electrons and gets reduced.

In our rocket fuel example, we determined that hydrazine, \(\text{N}_{2}\text{H}_{4}\), becomes oxidized; therefore, it serves as the reducing agent. Meanwhile, dinitrogen tetroxide, \(\text{N}_{2}\text{O}_{4}\), gets reduced and thus acts as the oxidizing agent. Understanding the role each substance plays in a redox reaction is vital as it helps to unravel how and why certain substances interact chemically.