Chapter 13: Problem 117
Concentrated hydrochloric acid is usually available at a concentration of 37.7 percent by mass. What is its molar concentration? (The density of the solution is \(1.19 \mathrm{~g} / \mathrm{mL}\).)
Short Answer
Step by step solution
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Hydrochloric Acid
- Found in gastric acid, it aids digestion in the stomach.
- Used in various industrial processes such as metal refining and cleaning.
- It is usually handled carefully due to its corrosive nature.
Mass Percentage
How to Calculate Mass Percentage
- Identify the mass of the solute.
- Measure the total mass of the solution.
- Use the formula: \[\text{Mass Percentage} = \left( \frac{\text{mass of solute}}{\text{total mass of solution}} \right) \times 100\]
- The result is given in percentage (%).
Density
Working with Density
The formula for density is:\[\text{Density} = \frac{\text{mass}}{\text{volume}}\]- For the current problem, the density of the HCl solution is 1.19 g/mL.
- This means for each milliliter of the solution, there are 1.19 grams of material.
- By using this density value, you can convert the volume of the solution (e.g., in liters) into its mass.
Molar Mass
Calculating Molar Mass
- For hydrochloric acid, the molecular formula is HCl.
- The molar mass of H (hydrogen) is about 1.01 g/mol and Cl (chlorine) is about 35.45 g/mol.
- Therefore, the molar mass of HCl is:\[1.01 \, \text{g/mol} + 35.45 \, \text{g/mol} = 36.46 \, \text{g/mol}\]
Solution Chemistry
- Solutions are homogenous mixtures of two or more substances.
- The solute is the substance that is dissolved, while the solvent is the substance in which the solute is dissolved.
- Molarity ( M ) is a key way to express solution concentration, defined as moles of solute per liter of solution.