Overview
This lecture solves all important MCQs from Mehran University Chemistry past papers and provides their brief explanations. Answers to key questions and related concepts are clarified for exam preparation.
Important Chemistry Concepts
- The amount of solute per kilogram of solution is called molality.
- The formula of methanol is CH₃OH.
- A hydrocarbon with at least one triple bond is called an alkyne.
- According to Charles's Law, increasing temperature at constant pressure increases volume.
- Adding water to a substance is called hydration.
- There are 8 main groups in the periodic table.
- Silicon and germanium are semiconductors.
- Alkali metals are the most reactive.
- If the electronegativity difference between two elements is less than 1.7, a covalent bond forms.
- The attractive force between liquid molecules is called cohesive force.
- Ionic compounds are generally solids at room temperature.
- Amino acids have three groups: acidic, basic, and amphoteric.
- In chemical equilibrium, the concentrations of reactants and products remain constant.
- Corrosion of metals mainly produces oxides.
- Cobalt is suitable for making permanent magnets.
- Metals are good conductors because they have free electrons.
Key Questions and Answers
- Charles's Law: V ∝ T (Volume is proportional to temperature at constant pressure)
- Barometer: Instrument to measure atmospheric pressure
- Base: Substance that gives hydroxide ions in water.
- Reducing agent: Alkali metals (easily lose electrons)
- Hydrogen bomb: Based on nuclear fusion
- Electron was discovered by J.J. Thomson.
- One mole of any gas occupies 22.4 liters at STP.
- Most electronegative element: Fluorine (4.0)
- 180 grams of glucose contains 1 mole of molecules.
- pH range is 0-14 and pOH range is also 0-14.
- In chemical equilibrium, concentrations of reactants and products do not change.
Key Terms & Definitions
- Molality — Moles of solute per kilogram of solvent in a solution.
- Cohesive Force — Attractive force between liquid molecules.
- Semiconductor — Substances that partially conduct electricity.
- Charles's Law — Volume is proportional to temperature at constant pressure.
- Galvanic Cell — Cell that converts chemical energy into electrical energy.
- Catalyst — Substance that increases reaction rate without being consumed.
- Ionic Compound — Solid crystalline compounds formed by ions.
Action Items / Next Steps
- Contact the given number to obtain the lecture PDF or past papers.
- Revise all MCQs and concepts.
- Practice examples of Charles's Law, gas laws, oxidation numbers, and electrochemistry.
- Review key concepts before the upcoming test.