Chemistry

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Showing 1351 to 1375 of 1398 questions (page 55 of 56).

1351. The notation used to represent a nuclide gives the mass number as a

A. subscript before the symbol B. superscript after the symbol C. superscript before the symbol D. separate word only E. subscript after the symbol

1352. The energy of an electron in the nth level of a hydrogen atom is proportional to

A. n squared B. the reciprocal of n squared C. the square root of n D. the reciprocal of n E. n

1353. The bond angle in the ammonium ion is about

A. 104.5 degrees B. 90 degrees C. 107 degrees D. 109.5 degrees E. 120 degrees

1354. The carbonate ion is

A. pyramidal B. bent C. tetrahedral D. linear E. trigonal planar

1355. The nitrogen atom in ammonia is

A. sp2 hybridized B. sp hybridized C. sp3d hybridized D. sp3 hybridized E. unhybridized

1356. The two oxygen to oxygen bonds in ozone are of equal length because of

A. ionic character B. hydrogen bonding C. resonance between two equivalent structures D. sp3 hybridization E. free rotation

1357. The electron pair geometry and molecular geometry differ whenever the central atom has

A. only bonding pairs B. one or more lone pairs C. a double bond D. hydrogen atoms attached E. an expanded octet

1358. Bond formation is always

A. spontaneous only at high temperature B. athermal C. endothermic D. exothermic E. accompanied by an increase in enthalpy

1359. The enthalpy of hydration of an ion is the enthalpy change when one mole of the gaseous ion

A. is oxidized B. is formed from the element C. is dissolved in a large excess of water D. loses an electron E. is vaporized

1360. At equilibrium, the rates of the forward and reverse reactions are

A. unrelated B. both zero C. in the ratio of the stoichiometric coefficients D. increasing steadily E. equal and non-zero

1361. A catalyst affects a reversible reaction by

A. reducing the time taken to reach equilibrium B. increasing the yield of product C. shifting the equilibrium right D. raising the equilibrium constant E. lowering the enthalpy change

1362. A strong electrolyte in aqueous solution is one that is

A. a poor conductor B. almost completely ionized C. molecular in solution D. sparingly soluble E. always an acid

1363. On the usual pH scale at 25 degrees Celsius, values run from

A. 0 to 7 B. 7 to 14 C. 0 to 14 D. 1 to 10 E. minus 7 to plus 7

1364. Increasing the concentration of a reactant in a system at equilibrium

A. stops the reaction B. changes the equilibrium constant C. shifts the equilibrium towards the reactants D. has no effect E. shifts the equilibrium towards the products

1365. The scattering of a light beam by a colloidal dispersion is known as the

A. Tyndall effect B. Doppler effect C. Zeeman effect D. Brownian effect E. Raman effect

1366. A colloid differs from a true solution mainly in the

A. electrical charge of the solvent B. colour of the dispersion C. temperature required D. size of the dispersed particles E. presence of a solvent

1367. Milk is an example of

A. a gel B. a true solution C. a foam D. an aerosol E. an emulsion

1368. A solution that contains more dissolved solute than its equilibrium solubility at that temperature is called

A. supersaturated B. unsaturated C. saturated D. colloidal E. dilute

1369. In standard cell notation, the anode half cell is written

A. in the middle B. on the left C. on the right D. only for galvanic cells E. not at all

1370. Standard electrode potentials are measured with solutions of concentration

A. saturated at 373 K B. any concentration C. 1 mol kg-1 at 273 K D. 1 mol dm-3 at 298 K and 1 atm E. 0.1 mol dm-3 at 273 K

1371. In the electrolytic refining of copper, the impure metal forms the

A. container only B. cathode C. anode D. electrolyte E. salt bridge

1372. Anodizing aluminium produces a protective layer of

A. aluminium chloride B. zinc oxide C. aluminium hydroxide only D. aluminium metal E. aluminium oxide

1373. Cathodic protection of a buried steel pipeline uses a block of

A. lead B. silver C. copper D. magnesium or zinc E. carbon

1374. The unstable arrangement of atoms at the top of the energy barrier is called the

A. reactant pair B. catalyst C. activated complex D. intermediate product only E. product

1375. Powdering a solid reactant increases the reaction rate because it increases the

A. surface area available for reaction B. concentration of the solid C. molar mass D. activation energy E. temperature

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