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🇵🇰 COMSATS Admission Test · flashcards
COMSATS Admission Test Chemistry Flashcards
50 question-and-answer cards covering Chemistry as it is examined in COMSATS Admission Test. 24 of them are printed below, taken from across the deck — no signup, no paywall on the preview.
24 sample cards from the Chemistry deck
Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.
What hybridization, geometry, and bond angle correspond to sp orbitals?
sp hybridization: linear geometry, 180° bond angle (2 electron domains), e.g., BeCl₂, C₂H₂.
What hybridization, geometry, and bond angle correspond to sp² orbitals?
sp² hybridization: trigonal planar geometry, 120° bond angle (3 electron domains), e.g., BF₃, C₂H₄.
What hybridization, geometry, and bond angle correspond to sp³ orbitals?
sp³ hybridization: tetrahedral geometry, 109.5° bond angle (4 electron domains), e.g., CH₄.
What hybridizations correspond to trigonal bipyramidal and octahedral geometries?
sp³d = trigonal bipyramidal (90° and 120°), e.g., PCl₅; sp³d² = octahedral (90°), e.g., SF₆.
What does VSEPR theory state?
Valence Shell Electron Pair Repulsion theory: electron pairs (bonding and lone) around a central atom arrange themselves to be as far apart as possible to minimize repulsion, determining molecular geometry.
Why is the H-O-H bond angle in water (104.5°) less than the ideal tetrahedral angle (109.5°)?
Water's oxygen has two lone pairs whose stronger lone pair-lone pair and lone pair-bond pair repulsions compress the bonding angle below 109.5°.
Rank the relative repulsion strengths between lone pairs (lp) and bond pairs (bp).
Lone pair-lone pair > lone pair-bond pair > bond pair-bond pair.
What is the molecular geometry of NH₃ and its approximate bond angle?
Trigonal pyramidal geometry (sp³ with one lone pair), bond angle about 107°.
State the postulates of the kinetic molecular theory of gases.
Gas particles are tiny and far apart (negligible volume); they move randomly in straight lines; collisions are perfectly elastic (no energy loss); there are no intermolecular forces; and average kinetic energy is proportional to absolute temperature.
State Boyle's Law with its equation.
At constant temperature and amount of gas, the volume is inversely proportional to pressure: PV = constant, or P₁V₁ = P₂V₂.
State Charles's Law with its equation.
At constant pressure and amount of gas, the volume is directly proportional to absolute temperature: V/T = constant, or V₁/T₁ = V₂/T₂.
State Avogadro's Law.
At constant temperature and pressure, equal volumes of all gases contain equal numbers of molecules; volume is directly proportional to the number of moles (V ∝ n).
Write the ideal gas equation and define each term.
PV = nRT, where P = pressure, V = volume, n = number of moles, R = universal gas constant (0.0821 L·atm·mol⁻¹·K⁻¹ or 8.314 J·mol⁻¹·K⁻¹), and T = absolute temperature in Kelvin.
State Dalton's Law of Partial Pressures.
The total pressure of a mixture of non-reacting gases equals the sum of the partial pressures of the individual gases: P_total = P₁ + P₂ + P₃ + ...
What is the molar volume of an ideal gas at STP, and what are the STP conditions?
22.414 L per mole at STP (Standard Temperature and Pressure: 0°C / 273.15 K and 1 atm / 101.325 kPa).
State Graham's Law of Diffusion/Effusion.
The rate of diffusion or effusion of a gas is inversely proportional to the square root of its molar mass (or density): rate ∝ 1/√M, so rate₁/rate₂ = √(M₂/M₁).
What is vapor pressure, and how does it relate to boiling point?
Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid. A liquid boils when its vapor pressure equals the external (atmospheric) pressure; lower external pressure lowers the boiling point.
Define surface tension and viscosity of a liquid.
Surface tension is the energy/force at a liquid surface that minimizes surface area (due to inward intermolecular attraction). Viscosity is a liquid's resistance to flow. Both generally increase with stronger intermolecular forces and decrease with rising temperature.
Compare crystalline and amorphous solids.
Crystalline solids have a regular, long-range ordered arrangement of particles, sharp melting points, and are anisotropic (e.g., NaCl, diamond). Amorphous solids lack long-range order, soften over a temperature range, and are isotropic (e.g., glass, rubber).
What is the coordination number in a crystal lattice?
The number of nearest-neighbor particles immediately surrounding a given particle (atom or ion) in the crystal structure.
Define a mole and state the value of Avogadro's number.
A mole is the amount of substance containing as many entities as there are atoms in 12 g of carbon-12. Avogadro's number = 6.022 × 10²³ entities per mole.
How do you calculate the number of moles from a given mass of a substance?
Moles (n) = mass (g) ÷ molar mass (g/mol).
What is the difference between an empirical formula and a molecular formula?
The empirical formula gives the simplest whole-number ratio of atoms in a compound (e.g., CH); the molecular formula gives the actual number of atoms of each element in a molecule (e.g., C₆H₆ for benzene). Molecular formula = (empirical formula)ₙ.
What is a limiting reactant, and how does it relate to theoretical yield and percent yield?
The limiting reactant is the reactant completely consumed first, which limits the amount of product formed. It determines the theoretical (maximum) yield. Percent yield = (actual yield ÷ theoretical yield) × 100%.
What this deck covers
The Chemistry deck follows the COMSATS Admission Test Chemistry syllabus — 11 chapters and 28 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 4.5 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 151 characters, which is long enough to carry the reasoning and short enough to say out loud.
A deck like this earns its keep on the second and third pass. Read the syllabus first so you know the shape of the subject, then use the cards to find the specific facts that have not stuck.
Chemistry flashcards FAQ
How many Chemistry flashcards are in this COMSATS Admission Test deck?
50 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these COMSATS Admission Test flashcards free?
Yes. The preview here is free to read with no signup, and the full 50-card deck is free inside the Examius app.
What do the Chemistry cards cover?
They follow the COMSATS Admission Test Chemistry syllabus — 11 chapters and 28 topics — so the questions track what is actually examinable.
How should I use these flashcards?
Read the syllabus first so you know the shape of the subject, then drill the deck. Examius schedules each card with spaced repetition, so cards you keep missing come back sooner and ones you know drift further apart.