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measures how a is by calculating moles of per liter of solution. It's crucial for comparing solutions and doing chemistry calculations. Knowing molarity helps you understand how much stuff is in a liquid.

You can calculate molarity by finding the moles of and volume of solution in liters. This involves converting mass to moles and volume to liters. problems use the equation M1V1 = M2V2 to figure out new concentrations when adding more .

Molarity and Solution Concentration

Concept of molarity

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Top images from around the web for Concept of molarity

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  • Measures of solutions by calculating moles of solute per liter of solution
    • Expressed as moles of soluteliters of solution\frac{\text{moles of solute}}{\text{liters of solution}}
    • Commonly used in chemistry to quantify solution ( in water)
  • Enables comparison of different solution concentrations and facilitates stoichiometric calculations
    • Higher molarity signifies more concentrated solution, lower molarity indicates more (0.1 vs 1.0 M sugar solution)
  • Varies with temperature due to changes in solution volume
    • Typically reported at standard temperature, often 25°C (room temperature)
    • Molarity decreases with increasing temperature as volume expands (heating 1.0 M solution)

Molarity calculations and unit conversions

  • Calculate molarity by determining moles of solute and volume of solution in liters
    1. Convert mass of solute to moles using
      • represents mass of one mole of substance, usually in grams per mole ()
      • Moles of solute=mass of solutemolar mass of solute\text{Moles of solute} = \frac{\text{mass of solute}}{\text{molar mass of solute}}
    2. Convert solution volume to liters if needed
      • Apply conversion factors to convert from other units to liters (mL to L)
  • Example: Find molarity of solution with 25.0 g NaCl in 500 mL solution
    1. Molar mass of NaCl = 58.44 g/mol
    2. Moles of NaCl=25.0 g58.44 g/mol=0.428 mol\text{Moles of NaCl} = \frac{25.0\text{ g}}{58.44\text{ g/mol}} = 0.428\text{ mol}
    3. Volume of solution = 500 mL = 0.500 L
    4. Molarity=0.428 mol0.500 L=0.856 M\text{Molarity} = \frac{0.428\text{ mol}}{0.500\text{ L}} = 0.856\text{ M}

Solution dilution and concentration problems

  • Dilution involves adding more to decrease solution concentration
    • Moles of solute stays constant, but solution volume increases
    • M1V1=M2V2M_1V_1 = M_2V_2, where M1M_1, V1V_1 are initial molarity and volume, M2M_2, V2V_2 are final molarity and volume
  • Solve dilution problems using M1V1=M2V2M_1V_1 = M_2V_2 equation
    1. Identify known values (initial molarity, volume, final molarity or volume)
    2. Solve for unknown value using algebra
  • Example: 2.00 M solution diluted to 1.00 L using 100 mL of original solution. Find final concentration.
    • M1=2.00 MM_1 = 2.00\text{ M}, V1=100 mL=0.100 LV_1 = 100\text{ mL} = 0.100\text{ L}, V2=1.00 LV_2 = 1.00\text{ L}
    • M1V1=M2V2M_1V_1 = M_2V_2
    • (2.00 M)(0.100 L)=M2(1.00 L)(2.00\text{ M})(0.100\text{ L}) = M_2(1.00\text{ L})
    • M2=(2.00 M)(0.100 L)1.00 L=0.200 MM_2 = \frac{(2.00\text{ M})(0.100\text{ L})}{1.00\text{ L}} = 0.200\text{ M}

Solution Preparation and Concentration

  • Concentration refers to the amount of solute dissolved in a given amount of solvent or solution
  • A solution is a homogeneous mixture of two or more substances
  • Volumetric flasks are used to accurately prepare solutions of known concentration
  • Stock solutions are concentrated solutions used to prepare more solutions for experiments

Key Terms to Review (25)

Concentrated: A solution is concentrated when it contains a high amount of solute relative to the amount of solvent. Concentrated solutions have higher molarity values, indicating more solute per unit volume of solution.
Concentration: Concentration is the measure of the amount of a solute that is dissolved in a given quantity of solvent. It is commonly expressed in terms of molarity (M), which is moles of solute per liter of solution.
Concentration: Concentration is a measure of the amount of a substance present in a given volume or mass of a solution or mixture. It is a fundamental concept in chemistry that is closely related to the study of chemical reactions, equilibrium, and the behavior of solutions.
Dilute: Dilute refers to a solution that has a relatively low concentration of solute compared to the solvent. It is achieved by adding more solvent to decrease the overall concentration of the solute.
Dilute Solution: A dilute solution is a type of solution where the concentration of the solute is relatively low compared to the solvent. This means the solution contains a small amount of dissolved substance dispersed throughout a larger volume of the solvent.
Dilution: Dilution is the process of reducing the concentration of a solute in a solution, usually by mixing with more solvent. It is often used to achieve desired molarity for experiments.
Dissolved: Dissolved describes a state in which a solute is uniformly dispersed within a solvent, forming a solution. The solute particles are at the molecular or ionic level.
G/mol: g/mol, or grams per mole, is a unit that expresses the molar mass or formula mass of a substance. It represents the mass of one mole of a particular substance, providing a way to quantify the amount of a chemical compound based on its molecular or atomic composition.
H2O: H2O, or water, is a chemical compound consisting of two hydrogen atoms covalently bonded to a single oxygen atom. It is a colorless, odorless, and tasteless liquid that is essential for life on Earth, playing crucial roles in various chemical and physical processes across multiple topics in chemistry.
KCl: KCl, or potassium chloride, is an ionic compound consisting of one potassium (K+) cation and one chloride (Cl-) anion. It is an important compound in the context of ionic and molecular compounds, molarity, and the occurrence and preparation of representative metals.
M: M is a widely used term in chemistry that represents various important concepts, including molarity, stoichiometry, effusion and diffusion, rate laws, and precipitation and dissolution. This versatile term is crucial for understanding and applying fundamental chemical principles across multiple topics in the field of chemistry.
Mol/L: Mol/L, also known as molarity, is a measure of the concentration of a substance in a solution. It represents the number of moles of a solute dissolved in one liter of the solution. Molarity is a fundamental concept in chemistry that is essential for understanding chemical reactions, equilibrium, and precipitation processes.
Molar mass: Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all atoms in the molecular formula.
Molar Mass: Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It is a fundamental concept in chemistry that relates the mass of a substance to the number of particles (atoms, molecules, or ions) it contains, and is essential for understanding chemical formulas, stoichiometry, and the behavior of gases.
Molarity: Molarity is a measure of the concentration of a solution, specifically the number of moles of a solute dissolved per liter of solution. It is a fundamental concept in chemistry that is used to quantify the amount of a substance present in a given volume of a solution and is essential for understanding various chemical processes and analyses.
Molarity (M): Molarity (M) is a measure of the concentration of a solute in a solution, expressed as moles of solute per liter of solution. It is commonly used to quantify the concentration of chemical solutions in laboratory settings.
NaCl: NaCl, commonly known as sodium chloride, is a chemical compound that consists of one sodium atom (Na) and one chlorine atom (Cl) bonded together. It is an ionic compound that is essential for various biological and industrial processes, and it is the primary component of table salt.
Saturated Solution: A saturated solution is a solution in which the maximum amount of a substance has been dissolved at a given temperature. The solution is in equilibrium with undissolved particles of the solute, and no more solute can be dissolved without the precipitation of the excess.
Solute: A solute is a substance that is dissolved in a solvent to form a solution. It can be in any phase: solid, liquid, or gas.
Solute: A solute is the substance that is dissolved in a solution, typically in smaller quantities compared to the solvent. It is the component of a solution that is present in a lesser amount and is dispersed throughout the solvent.
Solution: A solution is a homogeneous mixture composed of two or more substances. In a solution, a solute is dissolved in a solvent, resulting in a single phase with a uniform composition and properties throughout.
Solvent: A solvent is a substance, typically a liquid, that dissolves a solute to form a solution. The solvent is usually present in greater amount compared to the solute.
Solvent: A solvent is a liquid, solid, or gas that can dissolve other substances, known as solutes, to form a solution. Solvents play a crucial role in various chemical processes, including chemical reactions, extraction, and purification.
Stock Solution: A stock solution is a concentrated solution of a chemical substance that is used as a source to prepare other solutions with lower concentrations. It serves as a starting point for making dilutions or other chemical preparations.
Volumetric Flask: A volumetric flask is a type of laboratory glassware used to prepare and measure precise volumes of solutions. It is a commonly used tool in chemistry, particularly in the context of molarity calculations and other concentration-based analyses.
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Glossary
Glossary
3.4 Other Units for Solution Concentrations