Chemistry

Free set

Showing 751 to 775 of 1398 questions (page 31 of 56).

751. 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

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

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

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

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

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

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

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

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

756. 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. opposite spins D. the same orbital E. the same energy

757. The neutron was discovered by

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

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

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

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

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

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

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

761. The bond order in a nitrogen molecule is

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

762. Which of the following molecules is polar?

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

763. Metallic bonding is best described as

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

764. The standard conditions for reporting thermochemical data are

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

765. The enthalpy of combustion of a substance is always

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

766. In calorimetry, the heat exchanged is calculated from

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

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

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

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

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

769. A reversible reaction never goes to completion because

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

770. Raising the temperature of an exothermic reaction at equilibrium

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

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

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

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

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

773. An aqueous solution of sodium acetate is

A. acidic B. basic C. amphoteric D. a buffer on its own only at pH 7 E. neutral

774. The solubility product expression for silver chloride is

A. [Ag+][Cl-] B. [Ag+]2[Cl-] C. [Ag+]/[Cl-] D. [Ag+][Cl-]2 E. [AgCl]/[Ag+][Cl-]

775. Dissolving 0.5 mol of solute in enough water to make 250 cm3 of solution gives a molarity of

A. 0.5 M B. 0.125 M C. 1 M D. 2 M E. 5 M

Previous 1 2 … 29 30 31 32 33 … 55 56 Next

Get full access to the MCQ bank

Premium questions, timed mock tests, and detailed explanations.

See premium plans