SOLUTIONS in 103 Minutes || Full Chapter Revision || Class 12th NEET

Competition Wallah2 minutes read

Soil and sugar have different compositions, while homogeneous mixtures show the ability to store charge. Molality varies slightly in solvents, and the dielectric constant determines the solvent component in a solution.

Insights

  • A solution is a uniform mixture of two or more substances, where the solvent dissolves the solute, forming a homogeneous blend that cannot be visually distinguished.
  • Vapor pressure, crucial for understanding equilibrium in solutions, is influenced by temperature and intermolecular forces, with solute addition decreasing vapor pressure.
  • Colligative properties, such as vapor pressure lowering and boiling point elevation, depend on the number of solute particles in a solution, impacting essential physical properties like freezing and boiling points.

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Recent questions

  • What is a homogeneous mixture?

    A mixture with uniform composition and indistinguishable components.

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Summary

00:00

"Understanding Homogeneous Mixtures and Solutions"

  • Soil is a mixture of two substances, while sugar is a homogeneous mixture.
  • A homogeneous mixture shows the ability to store charge and has a dielectric constant.
  • Molality is one kilogram and varies slightly in different solvents.
  • Solute is a separate vapor of each liquid in a solution.
  • Pressure in a solution determines which component has more.
  • A solution is a homogeneous mixture of two or more substances.
  • Homogeneous mixtures are uniform in composition and indistinguishable by sight.
  • Solutions can be binary, ternary, or quaternary based on the number of components.
  • The component that dissolves others is the solvent, while the dissolved component is the solute.
  • The dielectric constant determines which component acts as the solvent in a solution, with water being a universal solvent due to its high dielectric constant.

16:29

Understanding Solutions and Concentrations in Chemistry

  • Air is a mixture of oxygen (O2) and nitrogen (N2), forming a homogeneous mixture.
  • A homogeneous mixture is also known as a solution, where components cannot be distinguished visually.
  • Solutions are not limited to liquids; examples include solid alloys and gaseous air.
  • Concentration in solutions refers to the amount of solute present, with terms like percentage by weight and volume explained.
  • Molarity is a concentration term denoting the number of moles of solute in 1 liter of solution.
  • Molarity calculations involve determining the molecular weight of the solute and dividing the given weight by it.
  • Molality, another concentration term, shows the moles of solute in 1 kilogram of solvent.
  • Mole fraction is a term used to calculate the ratio of moles of one component to the total moles in a mixture.
  • Vapor pressure is explained as the transition of liquid molecules to gas phase and back, reaching equilibrium in a closed vessel.
  • Equilibrium in vapor pressure occurs when the rates of evaporation and condensation become equal, maintaining a constant number of molecules transitioning between phases.

33:00

Gas Molecules and Vapor Pressure Dynamics

  • 10 molecules went up in one second, indicating a change in gas molecules.
  • The number of gas molecules remains fixed at equilibrium, proportional to pressure.
  • Vapor pressure is the pressure exerted by vapor above a liquid surface at equilibrium.
  • Vapor pressure depends on intermolecular forces of attraction in a liquid.
  • Increasing temperature increases vapor pressure by breaking bonds easily.
  • Vapor pressure increases exponentially with temperature.
  • Adding a non-volatile solute to a pure liquid decreases vapor pressure.
  • Rolt's Law calculates the vapor pressure of a component in a solution.
  • Mole fraction of a component in a solution determines its vapor pressure.
  • Vapor pressure of pure A can be calculated using Rolt's Law and mole fraction.

48:45

"Colligative Properties and Vapor Pressure in Solutions"

  • Addition of a volatile solute to a pure solvent leads to the creation of vapor.
  • The vapor pressure of the pure solvent is reduced when a volatile solute is added.
  • The total vapor pressure of the solution is the sum of the vapor pressures of the solvent and the solute.
  • Dalton's Law of Partial Pressure is applied to determine the total vapor pressure of the solution.
  • Roult's Law is used to calculate the vapor pressure of a component in the solution.
  • Colligative properties are those that depend solely on the number of solute particles in a solution.
  • Four colligative properties are discussed: relative lowering of vapor pressure, elevation in boiling point, depression in freezing point, and osmotic pressure.
  • Relative lowering of vapor pressure is a colligative property that depends on the mole fraction of the solute.
  • Elevation in boiling point occurs when a non-volatile solute is added to a solvent, requiring an increase in vapor pressure to reach the boiling point.
  • Boiling point is the temperature at which the vapor pressure of a liquid equals atmospheric pressure.

01:04:34

Effects of Temperature and Solute on Solutions

  • To increase vapor pressure, higher temperature is required for a pure solution.
  • Vapor pressure decreases when a solute is added to a solution, reducing it from 4 ATM to a lower value like 2 ATM.
  • Increasing temperature leads to higher vapor pressure, with boiling occurring at 100 degrees for pure water.
  • Boiling point elevation occurs when a volatile solute is added, increasing the boiling point above 100 degrees.
  • Vapor pressure reduction is seen when a volatile solute is added, causing a decrease in vapor pressure.
  • Elevation in boiling point is directly proportional to molality, with the elevation constant varying for different solvents.
  • Depression in freezing point occurs when a non-volatile solute is added, reducing the freezing point compared to the pure solvent.
  • The freezing point depression is proportional to the amount of solute added, with the cryoscopic constant specific to each solvent.
  • Osmotic pressure is a colligative property exerted by a solution due to the reverse flow of solvent through a semi-permeable membrane.
  • Osmotic pressure formula should be memorized to understand and calculate the pressure exerted by the solution.

01:20:55

Solution Concentration and Colligative Properties Explained

  • Molar concentration refers to the concentration of a solution in moles per liter.
  • Osmotic pressure is applied when there is a difference in concentration between two solutions.
  • In osmosis, water moves from an area of lower solute concentration to an area of higher solute concentration.
  • The colligative properties of solutions depend on the number of solute particles present.
  • Electrolytes are substances that break down into ions in solution.
  • Strong electrolytes completely dissociate into ions, affecting colligative properties.
  • Weak electrolytes partially dissociate, impacting colligative properties based on their degree of dissociation.
  • Henry's Law explains the solubility of gases in liquids, stating that the pressure of a gas is proportional to its concentration in the liquid.
  • The Henry constant varies for different liquid-gas pairs, affecting the solubility of gases.
  • Solubility decreases with increasing temperature, as more gas molecules escape the liquid.

01:37:48

Gas Solubility Laws and Solution Deviations

  • Henry's Law states that the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid.
  • According to Rolt Law, ideal solutions follow the law, while non-ideal solutions do not, with dilute solutions generally adhering to Rolt Law.
  • Non-ideal solutions can exhibit positive or negative deviations based on changes in the force of attraction between solvent molecules upon the addition of a solute.
  • Positive deviation occurs when the force of attraction between solvent molecules decreases upon adding a solute, while negative deviation happens when this force increases, affecting volume and enthalpy changes.
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