Problem 56 - Chemistry: The Central Science

Question

What parts of balanced chemical equations give information about the relative numbers of moles of reactants and products involved in a reaction?

Step-by-Step Solution

Answer

The stoichiometric coefficients in a balanced chemical equation provide information about the relative number of moles of reactants and products involved in a reaction. These coefficients represent the mole-to-mole ratio between reactants and products, indicating the proportions of substances in the reaction. For example, in the balanced equation 2H2 + O2 -> 2H2O, the coefficients 2 (for H2), 1 (for O2), and 2 (for H2O) tell us that 2 moles of hydrogen gas react with 1 mole of oxygen gas to produce 2 moles of water.

Step 1: Balance the equation and identify coefficients

\(A\) balanced chemical equation is a representation of a chemical reaction with the correct proportions of reactants and products. It follows the Law of Conservation of Mass, meaning that the total mass of the reactants is equal to the total mass of the products. In other words, the number of atoms of each element remains the same before and after the reaction. Here is an example: Unbalanced: H2 + O2 -> H2O Balanced: 2H2 + O2 -> 2H2O We can see that the balanced equation has coefficients (the numbers in front of each chemical species). These coefficients are adjusted to ensure the number of atoms of each element is the same on both sides of the equation.

Step 2: Understand the role of stoichiometric coefficients

In a balanced chemical equation, the coefficients (whole numbers) represent the relative number of moles of the reactants and products. These coefficients are called stoichiometric coefficients. They provide a mole-to-mole ratio between reactants and products, indicating the proportions of substances involved in the reaction. In our example above, the balanced equation is: 2H2 + O2 -> 2H2O The stoichiometric coefficients are: - 2 in front of H2 (reactant) - 1 in front of O2 (reactant) - 2 in front of H2O (product)

Step 3: Determine the mole-to-mole ratio of reactants and products

Using the stoichiometric coefficients, we can determine the relative amounts of moles of reactants and products involved in the reaction. In the example, the balanced equation tells us that when 2 moles of hydrogen gas (H2) react with 1 mole of oxygen gas (O2), they produce 2 moles of water (H2O). In general, these coefficients are used to compare how many moles of one substance react or are formed with another substance in a reaction.

Step 4: In conclusion

The parts of balanced chemical equations that give information about the relative number of moles of reactants and products involved in a reaction are the stoichiometric coefficients. By analyzing these coefficients, we can determine the mole-to-mole ratio between reactants and products, which is essential in stoichiometric calculations and understanding the proportions of substances involved in a chemical reaction.