When coal (essentially pure carbon) is burned, it combines with atmospheric oxygen to produce carbon dioxide gas. Nevertheless, when the coal burns, it seems to disappear. Why is this not a violation of the law of conservation of matter?

Chemical reactions are at the heart of chemistry, serving as the processes that change substances into different substances. To visualize what happens during a chemical reaction, consider the burning of coal. Coal, primarily made of carbon, reacts with oxygen in the air to form carbon dioxide. It's a transformation, but not a magic trick where matter vanishes.

In a chemical reaction, the reactants, which are the starting substances, undergo a chemical change to become the products, the new substances formed. In the case of burning coal, the reactant is the carbon in the coal and the oxygen in the air, while the product is carbon dioxide gas. What's fascinating is that the atoms in the reactants don't get destroyed; they just rearrange to form the products. This transformation exemplifies the law of conservation of matter—it's not that the coal disappears, but rather that it changes in a way that's not always immediately visible to the naked eye.

Balancing chemical equations is not just a formality; it's critically important. It's our way of ensuring that in a chemical reaction, the mass of the reactants equals the mass of the products, maintaining the law of conservation of matter. A balanced chemical equation reflects this law by showing the same number of each type of atom on both sides of the arrow.

Let's dive into the equation for the burning of coal: \[ C(s) + O_2(g) \rightarrow CO_2(g) \] This equation shows carbon (C) from coal reacting with oxygen (O2) to form carbon dioxide (CO2). Here, we have one carbon atom on both sides and two oxygen atoms on both sides. Since everything is equal, the equation is balanced, which confirms that no matter is lost in the process. When students practice balancing equations, they're leaning into the detective work of chemistry, ensuring that atoms are accounted for from beginning to end.

When coal burns, witnessing the substance seemingly disappear might puzzle some. To understand this, it's essential to look at what burning—or combustion—actually entails. Combustion is a high-temperature chemical reaction between a fuel and an oxidant, producing heat and light. With coal, it's the carbon reacting with oxygen, transforming solid coal into an entirely different state: carbon dioxide gas.

This gas then disperses into the atmosphere, and as it's invisible to the naked eye, the coal appears to have 'disappeared'. However, scientifically, we know this isn't a magic act; it's a classical illustration of the law of conservation of matter in action. During combustion, the atoms of carbon from the coal bond with oxygen atoms from the air to create a new substance—carbon dioxide. The matter is still there; it's just less apparent. This concept helps clarify to students why careful monitoring of gaseous emissions is crucial in environmental science and why despite coal seeming to vanish, it's releasing a substantial substance into our atmosphere.