Chemistry

Free set

Showing 451 to 475 of 1398 questions (page 19 of 56).

451. For an ideal gas, the compressibility factor Z is

A. 1 C. greater than 1 always D. equal to the pressure E. less than 1 always

452. Plasma differs from an ordinary gas in that it consists largely of

A. neutral atoms B. solid particles C. ions and free electrons D. molecules only E. liquid droplets

453. Evaporation of a liquid causes cooling because

A. the density increases B. the liquid absorbs cold from the air C. the pressure increases D. the volume decreases E. the fastest molecules escape, lowering the average kinetic energy of those left

454. London dispersion forces become stronger as

A. the molecule becomes smaller B. molar mass decreases C. temperature increases D. molar mass and polarizability increase E. the molecule becomes more polar

455. The property of crystals by which physical properties differ along different directions is called

A. isotropy B. polymorphism C. isomorphism D. cleavage E. anisotropy

456. Two substances with the same crystalline form and analogous chemical formulae are said to be

A. isotopic B. isomorphic C. polymorphic D. amorphous E. allotropic

457. The total number of orbitals in the shell with n = 2 is

A. 2 B. 9 C. 8 D. 4 E. 3

458. For l = 2, the number of permitted values of the magnetic quantum number is

A. 5 B. 3 C. 7 D. 1 E. 2

459. The Pauli exclusion principle states that no two electrons in an atom can have

A. the same spin B. identical values of all four quantum numbers C. the same energy D. the same orbital E. opposite spins

460. The neutron was discovered by

A. Millikan B. J J Thomson C. Rutherford D. Chadwick E. Bohr

461. The lines in the hydrogen emission spectrum arise when electrons

A. fall from higher to lower energy levels B. are shared between atoms C. move from lower to higher energy levels D. collide with the nucleus E. are ejected from the atom

462. The bond angle in water is about 104.5 degrees rather than 109.5 degrees because

A. hydrogen atoms repel each other B. the two lone pairs repel the bonding pairs more strongly C. of hydrogen bonding within the molecule D. the molecule is linear E. oxygen is sp2 hybridized

463. A sigma bond is stronger than a pi bond because

A. it involves fewer electrons B. it involves sideways overlap C. it involves head on overlap giving greater electron density between the nuclei D. it is formed later E. it uses unhybridized orbitals

464. The bond order in a nitrogen molecule is

A. 3 B. 2.5 C. 1.5 D. 1 E. 2

465. Which of the following molecules is polar?

A. boron trifluoride B. carbon tetrachloride C. carbon dioxide D. methane E. hydrogen chloride

466. Metallic bonding is best described as

A. the transfer of electrons from metal to non-metal B. hydrogen bonding between metal atoms C. the sharing of electron pairs between two atoms D. the electrostatic attraction between cations and a sea of delocalized electrons E. dipole induced dipole attraction

467. The standard conditions for reporting thermochemical data are

A. 298 K and 10 atm B. 0 K and 1 atm C. 273 K and 1 atm D. 373 K and 1 atm E. 298 K and 1 atm

468. The enthalpy of combustion of a substance is always

A. zero B. negative C. equal to the lattice energy D. equal to the enthalpy of formation E. positive

469. In calorimetry, the heat exchanged is calculated from

A. q = m c delta T B. q = m/c delta T C. q = nRT D. q = P delta V E. q = c delta T / m

470. A bomb calorimeter measures the heat of combustion at constant

A. pressure B. entropy C. temperature D. enthalpy E. volume

471. Internal energy is a state function, which means it depends on

A. the path taken B. only the initial and final states C. the container shape D. the catalyst used E. the time taken

472. A reversible reaction never goes to completion because

A. the pressure drops B. the temperature falls C. the reverse reaction becomes appreciable as products accumulate D. the reactants are impure E. the catalyst is exhausted

473. Raising the temperature of an exothermic reaction at equilibrium

A. increases Kc B. has no effect C. stops the reaction D. shifts it towards the products E. shifts it towards the reactants

474. The pH of pure water at 25 degrees Celsius is

A. 14 B. 8 D. 7 E. 6

475. A larger value of the acid dissociation constant Ka indicates

A. a weaker acid B. a neutral solution C. a stronger acid D. a stronger base E. a buffer solution

Previous 1 2 … 17 18 19 20 21 … 55 56 Next

Get full access to the MCQ bank

Premium questions, timed mock tests, and detailed explanations.

See premium plans