Back to MCQ Bank

Chemistry

Free set

Showing 626 to 650 of 1398 questions (page 26 of 56).

626. The reactant that is completely consumed first and therefore limits the amount of product is called the

A. intermediate B. limiting reactant C. catalyst D. spectator species E. excess reactant

627. A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass. Its empirical formula is

A. CH2O B. C2H4O2 C. C2H6O D. CH4O E. CHO

628. The number of moles in 9.8 g of sulphuric acid is

A. 0.2 B. 0.1 C. 1.0 D. 0.98 E. 0.05

629. The number of molecules in 11.2 dm3 of oxygen gas at STP is

A. 1.5 x 10^23 B. 1.204 x 10^24 C. 6.02 x 10^23 D. 3.01 x 10^23 E. 6.02 x 10^22

630. Isotopes of an element are separated on the basis of

A. chemical reactivity B. boiling point of the compound C. difference in colour D. difference in charge only E. difference in mass

631. A fluted filter paper is used in filtration to

A. increase the surface area available for filtration B. dry the precipitate C. remove coloured impurities D. reduce the pore size E. neutralize the filtrate

632. Which pair of substances can be purified by sublimation?

A. glucose and urea B. sodium chloride and sugar C. iodine and naphthalene D. ethanol and water E. copper sulphate and alum

633. In paper chromatography, the Rf value of a component is always

A. greater than 1 B. independent of the solvent C. negative D. equal to 1 E. less than or equal to 1

634. Solvent extraction is governed by the

A. law of definite proportions B. Hess's law C. law of mass action D. distribution law E. Raoult's law

635. A good solvent for crystallization should

A. react with the solute B. dissolve the solute more when hot than when cold C. have a very high boiling point only D. dissolve the impurities only when cold E. dissolve the solute equally well hot and cold

636. Boyle's law states that at constant temperature the volume of a given mass of gas is

A. proportional to the square of pressure B. directly proportional to pressure C. inversely proportional to pressure D. proportional to temperature E. independent of pressure

637. Extrapolation of the volume against temperature graph for a gas gives absolute zero at

A. -273.16 degrees Celsius B. -100 degrees Celsius C. -373 degrees Celsius D. 100 degrees Celsius E. 0 degrees Celsius

638. The value of the gas constant R in dm3 atm mol-1 K-1 is

A. 62.4 B. 1.987 C. 0.0821 D. 0.083 E. 8.314

639. According to Graham's law, the rate of diffusion of a gas is

A. proportional to its molar mass B. proportional to the square root of its molar mass C. proportional to the square of its molar mass D. inversely proportional to the square root of its molar mass E. independent of molar mass

640. In the van der Waals equation, the constant b accounts for

A. the volume occupied by the gas molecules B. the temperature correction C. the kinetic energy of the molecules D. intermolecular attraction E. the number of moles

641. A gas cannot be liquefied by pressure alone above its

A. boiling point B. critical temperature C. inversion temperature D. transition temperature E. melting point

642. The average kinetic energy of gas molecules is directly proportional to

A. molar mass B. density C. volume D. pressure E. absolute temperature

643. Dalton's law of partial pressures does not apply to gases that

A. are at low pressure B. are at high temperature C. are monatomic D. react chemically with each other E. have different molar masses

644. The abnormally high boiling point of water compared with hydrogen sulphide is due to

A. its ionic character B. hydrogen bonding C. covalent network bonding D. its low molar mass E. London dispersion forces

645. The boiling point of a liquid at reduced external pressure

A. decreases B. remains unchanged C. becomes zero D. increases E. doubles

646. The coordination number of each ion in a sodium chloride crystal is

A. 12 B. 4 C. 2 D. 8 E. 6

647. The existence of a substance in more than one crystalline form is called

A. allotropy in solutions only B. anisotropy C. polymorphism D. isotopy E. isomorphism

648. Which type of solid has the highest melting point?

A. amorphous B. molecular C. covalent network D. ionic E. metallic

649. The maximum number of electrons that can occupy the shell with n = 3 is

A. 6 B. 8 C. 10 D. 32 E. 18

650. For an electron in a 3d orbital, the azimuthal quantum number l is

A. 2 B. 4 C. 3 E. 1

Previous 1 2 … 24 25 26 27 28 … 55 56 Next

Get full access to the MCQ bank

Premium questions, timed mock tests, and detailed explanations.

See premium plans