Problem 46 - Chemistry Matter and Change

Question

Explain When fluorine gas combines with water vapor, the following reaction occurs. $$2 \mathrm{F}_{2}(\mathrm{g})+2 H_{2} O(\mathrm{g}) \rightarrow O_{2}(\mathrm{g})+4 \mathrm{HF}(\mathrm{g})$$ If the reaction starts with 2 L of fluorine gas, how many liters of water vapor react with the fluorine, and how many liters of oxygen and hydrogen fluoride are produced?

Step-by-Step Solution

Answer

In conclusion, when 2 liters of fluorine gas reacts with water vapor, it reacts with 2 liters of water vapor and produces 1 liter of oxygen gas and 4 liters of hydrogen fluoride.

Step 1: Write the balanced chemical equation

The balanced chemical equation for the reaction is already provided: \[2 F_2(g) + 2 H_2O(g) \rightarrow O_2(g) + 4 HF(g)\]

Step 2: Determine the stoichiometric ratios

According to the balanced chemical equation, for every 2 moles of fluorine gas (F2) that react, 2 moles of water vapor (H2O) are consumed and 1 mole of oxygen gas (O2) and 4 moles of hydrogen fluoride (HF) are produced. The stoichiometric ratios are: - F2 : H2O = 2 : 2 - F2 : O2 = 2 : 1 - F2 : HF = 2 : 4

Step 3: Determine the amount of water vapor reacted

Since the problem states that the reaction starts with 2 L of fluorine gas and assuming all of it reacts, we can calculate the amount of water vapor that reacts using the stoichiometric ratio of F2 to H2O (2:2): Amount of water vapor = Amount of fluorine gas x (Ratio of H2O to F2) Amount of water vapor = 2 L x (2/2) = 2 L So, 2 liters of water vapor reacts with the fluorine gas.

Step 4: Determine the amount of oxygen gas produced

To calculate the amount of oxygen gas produced, we can use the stoichiometric ratio of F2 to O2 (2:1): Amount of oxygen gas = Amount of fluorine gas x (Ratio of O2 to F2) Amount of oxygen gas = 2 L x (1/2) = 1 L So, 1 liter of oxygen gas is produced.

Step 5: Determine the amount of hydrogen fluoride produced

To calculate the amount of hydrogen fluoride, we can use the stoichiometric ratio of F2 to HF (2:4): Amount of hydrogen fluoride = Amount of fluorine gas x (Ratio of HF to F2) Amount of hydrogen fluoride = 2 L x (4/2) = 4 L So, 4 liters of hydrogen fluoride is produced. In conclusion, 2 liters of water vapor react with 2 liters of fluorine gas, and the reaction produces 1 liter of oxygen gas and 4 liters of hydrogen fluoride.

Key Concepts

Chemical reactions

Understanding chemical reactions is fundamental in studying chemistry. A chemical reaction involves the transformation of one or more substances, known as reactants, into one or more different substances, called products. These transformations occur as a result of the breaking and forming of chemical bonds, which may manifest as changes in color, the production of gas, the formation of a precipitate, or the release or absorption of energy.

For example, when fluorine gas reacts with water vapor, a chemical reaction takes place resulting in the formation of oxygen and hydrogen fluoride gases. In the classroom or lab, such reactions are explored to understand the behavior and properties of the involved compounds. Our ability to predict the outcomes of chemical reactions is crucial for everything from manufacturing products to understanding biological processes.

Balanced chemical equation

A balanced chemical equation is a representation of a chemical reaction that includes the number and type of atoms of each element involved in the reaction. It follows the law of conservation of mass which states that matter cannot be created or destroyed in a chemical reaction. Therefore, the number of atoms of each element must be the same on both sides of the equation.

In the equation for the reaction between fluorine gas and water vapor to produce oxygen and hydrogen fluoride (\(2 \text{F}_2(\text{g}) + 2 \text{H}_2 \text{O}(\text{g}) \rightarrow \text{O}_2(\text{g}) + 4 \text{HF}(\text{g})\)), the equation is balanced with 2 molecules of fluorine gas reacting with 2 molecules of water vapor to produce 1 molecule of oxygen gas and 4 molecules of hydrogen fluoride gas. This proportion ensures that the same amount of each element is present before and after the reaction. Achieving balance in a chemical equation is often the first step when solving stoichiometric problems.

Mole-to-mole ratio

The mole-to-mole ratio in a chemical reaction is derived from the coefficients of a balanced chemical equation. It reflects the proportions in which reactants combine and products form. This ratio is essential in stoichiometric calculations, which involve quantifying the amounts of substances consumed and produced in a chemical reaction.

For instance, the balanced chemical equation mentioned earlier provides significant information through mole-to-mole ratios such as the ratio of fluorine gas to water vapor (2:2), fluorine gas to oxygen gas (2:1), and fluorine gas to hydrogen fluoride (2:4). These ratios are pivotal for predicting how much of each reactant is needed and how much of each product will be formed. By understanding these ratios, we can solve practical problems, like calculating the amount of water vapor that will react with a given volume of fluorine gas and predicting the quantities of oxygen and hydrogen fluoride produced, simply using proportional relationships.