Question

Concentrated hydrochloric acid is made by pumping hydrogen chloride gas into distilled water. If concentrated \(\mathrm{HCl}\) contains \(439 \mathrm{~g}\) of \(\mathrm{HCl}\) per liter, what is the molarity?

Short answer

The molarity of concentrated hydrochloric acid containing \(439 \mathrm{~g}\) of \(\mathrm{HCl}\) per liter is approximately \(12.027\mathrm{~M}\).

Step-by-step solution

Calculate the moles of HCl in 1 liter

We are given the following information: Mass of \(\mathrm{HCl} = 439 \mathrm{~g}\) Molar mass of \(\mathrm{HCl} = 36.5 \mathrm{~g/mol}\) To calculate the moles of \(\mathrm{HCl}\) present in \(1\) liter, use the formula: Moles = (mass in grams) / (molar mass in g/mol) Moles = \(\frac{439\mathrm{~g}}{36.5\mathrm{~g/mol}}\)

Calculate the molarity

To determine the molarity, divide the moles of \(\mathrm{HCl}\) by the volume in liters: Molarity = Moles / Volume We calculated moles of \(\mathrm{HCl}\) in Step 1 and \(1 L\) is the volume in liters. Molarity = \(\frac{\frac{439\mathrm{~g}}{36.5\mathrm{~g/mol}}}{1\mathrm{~L}}\)

Simplify the expression

Now, simplify the expression to find the molarity: Molarity = \(\frac{439}{36.5} = 12.027 \mathrm{~M}\) So, the molarity of concentrated hydrochloric acid is approximately \(12.027\mathrm{~M}\).

Key concepts

Understanding Hydrochloric Acid

Hydrochloric acid, often represented as \(\mathrm{HCl}\), is a strong and corrosive acid that is commonly used in industrial and laboratory settings. It is created by dissolving hydrogen chloride gas into distilled water. While it is a component in various cleaning agents, it is also used in the production of gelatin and other household and industrial applications. Hydrochloric acid is a colorless solution that has a distinctive pungent smell, and it should be handled with care due to its strong acidic nature.

Basics of Moles Calculation

Calculating moles is a fundamental concept in chemistry that allows us to count particles, like atoms or molecules, in a given sample. The mole is a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules, or other specified particles. The number of moles can be calculated using the formula: Moles = \(\frac{\text{mass in grams}}{\text{molar mass in g/mol}}\). Understanding moles is crucial because it helps determine the amount of substance to use in chemical reactions, which is often needed to calculate concentration in solutions.

Concentration Calculation Simplified

Concentration in chemistry refers to the amount of a substance within a specific volume of solution. One of the most common ways to express concentration is molarity, denoted as \(M\), which is defined as the number of moles of solute per liter of solution. The formula for molarity is: Molarity = \(\frac{\text{Moles of solute}}{\text{Volume of solution in Liters}}\). Calculating the molarity helps chemists determine the strength of a given solution and its potential reactive capabilities. In our example, the molarity was calculated by determining the moles of \(\mathrm{HCl}\) dissolved in one liter of water.

Exploring Chemical Solutions

Chemical solutions are homogeneous mixtures composed of two or more substances. In a solution, the substance in the smallest amount, known as the solute, is dissolved in a larger amount of another substance, known as the solvent.

• Solute: the component of the solution that is dissolved.
• Solvent: the substance that dissolves the solute.

Chemical solutions are vital in chemistry because they allow for chemical reactions to occur between solutes and solvents. Solutions can have different concentrations, affecting their chemical behavior and the results of reactions. Understanding and calculating the concentration informs how solutions will interact in various applications, ensuring desired outcomes in industrial, laboratory, and everyday chemistry.